Cristofre Martin - Academia.edu (original) (raw)

Papers by Cristofre Martin

Research paper thumbnail of Tropical Marine Microbial Diversity of Potential Algal Degraders from Grenada W.I

Research paper thumbnail of EMBRYOGENESIS Ultrastructural Analysis of the Cell State Splitter in Ectoderm Cells Differentiating to Neural Plate and Epidermis during Gastrulation in Embryos of the Axolotl Ambystoma mexicanum

Abstract-We have confinned and elaborated the ultrastructur ~ of the "cell stat ~ splitter &... more Abstract-We have confinned and elaborated the ultrastructur ~ of the "cell stat ~ splitter " (CSS), a "morphogenetic organ~lle " that we think may be responsible for the differentiation of ectoderm cells into neural plate and epidermis, in the embryonic ~lls of the axolotl. Ambystoma mexicanum (a urodele amphibian). The CSS consists of an apical microfilament (MF) ring, a lower intermediate filament~(IF) ring, and a subteliding. annular, nearly coplanar mat of apical microtubules (MT), all within I ~ of the apif,:alend of the 50-100 J.Un tall cells. Th ~ IF ring is attached to the membrane via desmosomes, and the MF ring and apical MTs, may be so attached. The CSS is constructed inectodenn celts between early and mid-gastrula, coincident with: '(I) high concentrati()ns C)fribosomes that are membrane associated and apically localized, (2) an increase in global tension of the embryo, and (3) a furrowing wave of surface contraction 'that passes over the pr...

Research paper thumbnail of Environmental genomics. Preface

Methods in molecular biology, 2008

Research paper thumbnail of DNA methyltransferase in the zebrafish Danio rerio: 5-aza-cytidine treatment of embryos in vivo causes disruption in the development of the axial mesoderm

I have conducted sequence analysis of a zebrafish cDNA that encodes the protein DNA (5-cytosine) ... more I have conducted sequence analysis of a zebrafish cDNA that encodes the protein DNA (5-cytosine) methyltransferase. I show that during development transcription of this zebrafish DNA methyltransferase gene is most high at blastula where it is ubiquitously expressed. At 24 hours of development, highest expression is observed in the brain, neural tube, eyes, and differentiating somites. To further assess the role of DNA methylation during development, I treated zebrafish embryos with 5-aza-cytidine (5-azaC), a nucleotide analog known to induce cellular differentiation and DNA hypomethylation in mammalian cell cultures. Treatments with 5-azaC during blastula and early gastrula caused a perturbation of the body axis resulting in loss of tail, and loss or abnormal development of the somites. Histological sections and in situ hybridization revealed whole or partial loss of a differentiated notochord and mid-line muscle in treated embryos. There was loss of expression of no tail in the notochord and eng in muscle-pioneer cells at 24 hours. When examined during gastrulation, 5-azaC treated embryos has a shortened and thickened axial mesoderm. DNA analysis on 5-azaC-treated embryos indicated an overall decrease in DNA methylation when compared to untreated controls. Embryos treated with 6-aza-cytidine, a cytidine analog not known to affect DNA methylation, showed neither abnormal development nor hypomethylation. Our findings suggest that normal DNA methylation is required for proper differentiation of dorsal mesoderm and pattern development of the dorsal-ventral body axis.

Research paper thumbnail of Not just a fishing trip-Environmental genomics using zebrafish

Research paper thumbnail of Not just a fishing trip—environmental genomics using zebrafish

Abstract: Genetic diversity is the raw material needed by a species allowing adaptation to changi... more Abstract: Genetic diversity is the raw material needed by a species allowing adaptation to changing environmental conditions and thus ensuring long-term sustainability. The development of technologies for environmental genomics provides us with the opportunity to link information, at the whole genome level, with the response of an organism to its natural environment. Over the past 15 years a small tropical fish native to the rivers of India and south Asia, the zebrafish (Danio rerio), has become one of the most popular vertebrate model systems. Zebrafish are abundant and many populations exist that are reproductively isolated. They evolved under distinct environments, and this have lead to genetic diversity and, as a consequence, has created genotypic and phenotypic differences between the populations. For this fish species, a large number of molecular and genomic tools have been developed. As a result, the zebrafish has emerged as a popular model for the study of embryonic developm...

Research paper thumbnail of Environmental genomics

... Methods in Lipid Membranes, edited by Alex Dopico, 2007 399. Neuroprotection Methods and Prot... more ... Methods in Lipid Membranes, edited by Alex Dopico, 2007 399. Neuroprotection Methods and Protocols, edited by Tiziana Borsello, 2007 398. Lipid Rafts, edited by Thomas J. McIntosh, 2007 397. Hedgehog Signaling Protocols, edited by Jamila I. Horabin, 2007 396. ...

Research paper thumbnail of The Evolution of Perception

Http Dx Doi Org 10 1080 01969720151033553, Oct 29, 2010

Research paper thumbnail of Environmental genomics. Preface

Methods in molecular biology (Clifton, N.J.), 2008

Research paper thumbnail of A role for modifier genes in genome imprinting

Results and problems in cell differentiation, 1999

Research paper thumbnail of High-throughput whole mount in situ hybridization of zebrafish embryos for analysis of tissue-specific gene expression changes after environmental perturbation

Methods in molecular biology (Clifton, N.J.), 2008

Whole mount in situ hybridization is a process that allows the visualization of gene expression (... more Whole mount in situ hybridization is a process that allows the visualization of gene expression (mRNA) within the cells of an intact organism. By comparing gene expression domains between organisms that have been subjected to different environmental conditions, an understanding of the cellular and tissue-specific effects of these environmental exposures can be identified. This technique is complementary to gene expression profiling techniques such as DNA microarrays which can usually provide information only on the differential levels of gene expression within an organism or tissue. In the case of whole mount in situ hybridization there is the added ability to detect differences in the distribution of cells, within a whole organism, expressing a particular gene. Subtle changes in the distribution of cells expressing a gene may not be reflected in the overall level of gene expression when RNA samples are retrieved from a whole organism and assayed. Exploitation of automation technolo...

Research paper thumbnail of Specific craniofacial cartilage dysmorphogenesis coincides with a loss of dlx gene expression in retinoic acid-treated zebrafish embryos

Mechanisms of Development, 1997

Treatments of zebrafish embryos with retinoic acid (RA), a substance known to cause abnormal cran... more Treatments of zebrafish embryos with retinoic acid (RA), a substance known to cause abnormal craniofacial cartilage development in other vertebrates, result in dose-and stage-dependent losses of dlx homeobox gene expression in several regions of the embryo. Dlx expression in neural crest cells migrating from the hindbrain and in the visceral arch primordia is particularly sensitive to RA treatment. The strongest effects are observed when RA is administered prior to or during crest cell migration but effects can also be observed if RA is applied when the cells have entered the primordia of the arches. Losses of dlx expression correlate either with the loss of cartilage elements originating from hindbrain neural crest cells or with abnormal morphology of these elements. Cartilage elements that originate from midbrain neural crest cells, which do not express dlx genes, are less affected. Taken together with the observation that the normal patterns of visceral arch dlx expression just prior to cartilage condensation resemble the morphology of the cartilage elements that are about to differentiate, our results suggest that dlx genes are an important part of a multi-step process in the development of a subset of craniofacial cartilage elements.

Research paper thumbnail of Furrowing surface contraction wave coincident with primary neural induction in amphibian embryos

Journal of Morphology, 1994

... Custom time-lapse and focus-collage software used in this project was devel-oped by Andrew Ma... more ... Custom time-lapse and focus-collage software used in this project was devel-oped by Andrew MacLean and Andrea Mar-tinko, Department of Civil Engineering, University of Waterloo. ... Markin, VS, VF Pastushenko, and YA Chizmadzhev (1987) Theory of Excitable Media. ...

Research paper thumbnail of Differentiation trees, a junk DNA molecular clock, and the evolution of neoteny in salamanders

Journal of Evolutionary Biology, 1995

Research paper thumbnail of Stable Transfer of Zebrafish Chromosome Segments into Mouse Cells

Genomics, 1996

Whole-cell fusion between zebrafish fibroblast-like tools such as a genetic linkage map and a phy... more Whole-cell fusion between zebrafish fibroblast-like tools such as a genetic linkage map and a physical map ZF4 cells and mouse B78 melanoma cells resulted in of overlapping YAC, P1, or cosmid clones will facilitate hybrids containing one or a few zebrafish chromosome the cloning of genes that are affected in zebrafish musegments in a murine chromosomal background. Fluotants. Recently, a genetic linkage map of the zebrafish rescence in situ hybridization to hybrid cell metagenome has been reported (Postlethwait et al., 1994). phases with a zebrafish genomic DNA probe revealed The map consists of more than 400 random amplified that many hybrids contained zebrafish chromosome polymorphic DNAs (RAPDs) (Williams et al., 1990; segments that were either inserted or translocated to a Welsh and McClelland, 1990). It was originally orgamouse chromosome, whereas other hybrids contained nized into 29 linkage groups but has now been consolizebrafish chromosomes with no evidence of insertion dated into 25 linkage groups (S. L. Johnson and J. Postor translocation. We have assigned hybrids to 17 linklethwait, unpublished data), corresponding to the numage groups of the genetic map of the zebrafish genome. ber of zebrafish chromosomes identified by karyotype Our results demonstrate the feasibility of producing (Schreeb et al., 1993). The map has been complemented somatic cell hybrids between distantly related species. by the integration of anonymous DNA markers based Zebrafish/mouse cell hybrids will provide a useful tool upon simple sequence repeats (SSRs) (Goff et al., 1992) for the physical mapping of the zebrafish genome and and of cloned genes (Postlethwait et al., 1994). The for the cloning of genes affected in zebrafish mutants. linkage map of the zebrafish genome will contribute to ᭧ 1996 Academic Press, Inc. the molecular analysis of zebrafish mutations affecting development. Panels of human/mouse and mouse/hamster somatic Whole-cell fusion. Calcium phosphate precipitation (Maniatis et al., 1989) was used to transfer the pCMV neo plasmid into ZF4 cells.

Research paper thumbnail of Expression and genomic organization of the zebrafish chaperonin gene complex

Genome, 2002

Chaperonin 10 and chaperonin 60 monomers exist within the multimeric mitochondrial chaperonin fol... more Chaperonin 10 and chaperonin 60 monomers exist within the multimeric mitochondrial chaperonin folding complex with a stoichiometry of 2:1. This complex is located in the mitochondrial matrix, where it aids in the folding and acquisition of the tertiary structure of proteins. We have previously isolated the cpn10 cDNA in zebrafish (Danio rerio), and demonstrated that it is ubiquitously expressed during embryonic development and transcriptionally upregulated after exposure to heat shock. In the present study, we have isolated a cDNA encoding chaperonin 60 (cpn60) from zebrafish, and have shown that it is similarly expressed uniformly and ubiquitously throughout early embryonic development of zebrafish. Upregulation of cpn60 expression was also observed after exposure of zebrafish embryos to a heat shock of 1 h at 37°C compared with control embryos raised at 27°C. The induction of the cpn60 heat shock response was greatest after 1 h of heat shock, whereas significant decreases of cpn60...

Research paper thumbnail of Genotype-specific modifiers of transgene methylation and expression in the zebrafish, Danio rerio

Genetical Research, 1995

SummaryPrevious reports involving mammalian systems, particularly mice, have demonstrated the exi... more SummaryPrevious reports involving mammalian systems, particularly mice, have demonstrated the existence of cis- and trans-acting modifiers of transgene methylation. These modifiers are thought to be important in dominance modification, genome imprinting and cellular expression mosaicism. Their potential role in the penetrance and severity of many complex human diseases could be of even greater significance. In the present investigation we demonstrate that modifiers that act in a similar fashion to those identified in mice also exist in a non-mammalian vertebrate, the zebrafish Danio rerio. We also provide evidence that the transgene methylation pattern may be influenced by the sex of the individual and environmental modulators such as temperature and sodium butyrate. These data support the theory that this type of dominance modification is mechanistically similar to position effect variegation in Drosophila. Furthermore, these data suggest evolutionary conservation of the modifiers,...

Research paper thumbnail of Parent-of-origin specific effects on the methylation of a transgene in the zebrafish,Danio rerio

Developmental Genetics, 1995

... The similarity be-tween this mosaic transgene expression in zebrafish and our previously desc... more ... The similarity be-tween this mosaic transgene expression in zebrafish and our previously described mosaic transgene expres-sion in mice [McGowan et al., 19891 raised the possi-bility of a similar imprinting system operating ... Address reprint requests to Ross McGowan, Dept. ...

Research paper thumbnail of Differential expression of the methyl-cytosine binding protein 2 gene in embryonic and adult brain of zebrafish

Developmental Brain Research, 2004

Epigenetic gene repression occurs as the result of the interactions between DNA and a number of p... more Epigenetic gene repression occurs as the result of the interactions between DNA and a number of proteins, including methyl-cytosine binding protein 2 (MeCP2). We have isolated a 1680 bps MeCP2 cDNA from zebrafish that shows deduced amino acid identity with Xenopus and mammalian MeCP2a protein sequences. The zebrafish MeCP2 gene was mapped to linkage group 8 using the LN54 radiation hybrid cell panel. The genomic organizations of the zebrafish MeCP2 and mammalian MeCP2a are highly similar. Relatively high levels of expression of MeCP2 mRNA were found in embryos at 1 to 4 h postfertilization (hpf), after 24 hpf, and in adult brain and eyes. Whole mount in situ hybridization was performed on embryos and revealed ubiquitous MeCP2 expression during early zebrafish development. At 24 and 48 hpf, the highest levels of expression are found in the epiphysis, midbrain, ventricular zone, and the otic vesicles. In adult zebrafish, MeCP2-expressing cells were found throughout the brain. Regions that are enriched in MeCP2 mRNA include the pallium layer of the telencephalon, the preoptic area, the periventricular grey zone, lobus caudalis, and the vagus lobes. In the cerebellum, high expression is found in the Purkinje and Golgi type 2 cells.

Research paper thumbnail of Disruption of Zebrafish Somite Development by Pharmacologic Inhibition of Hsp90

Developmental Biology, 1999

Members of the Hsp90 family of molecular chaperones play important roles in allowing some intrace... more Members of the Hsp90 family of molecular chaperones play important roles in allowing some intracellular signaling molecules and transcription factors to reach and maintain functionally active conformations. In the present study, we have utilized the specific Hsp90-binding agent, geldanamycin, to examine the requirement for Hsp90 during zebrafish development. We show that geldanamycin interacts with both the ␣ and the ␤-isoforms of zebrafish Hsp90 and that geldanamycin-treated embryos consistently exhibit a number of defects in tissues which express either one of these genes. Within the somites, geldanamycin treatment results in the absence of eng-2-expressing muscle pioneer cells. However, early development of adaxial cells, which give rise to muscle pioneers and which strongly express the hsp90␣ gene shortly before muscle pioneer formation, appeared unaffected. Furthermore, development of the notochord, which provides many of the signals required for proper somite patterning and which does not express detectable levels of either hsp90␣ or hsp90␤ mRNA, was similarly unaffected in geldanamycin-treated embryos. The data are consistent with there being a temporal and spatial requirement for Hsp90 function within somitic cells which is necessary for the formation of eng-2-expressing muscle pioneers and possibly other striated muscle fiber types.

Research paper thumbnail of Tropical Marine Microbial Diversity of Potential Algal Degraders from Grenada W.I

Research paper thumbnail of EMBRYOGENESIS Ultrastructural Analysis of the Cell State Splitter in Ectoderm Cells Differentiating to Neural Plate and Epidermis during Gastrulation in Embryos of the Axolotl Ambystoma mexicanum

Abstract-We have confinned and elaborated the ultrastructur ~ of the "cell stat ~ splitter &... more Abstract-We have confinned and elaborated the ultrastructur ~ of the "cell stat ~ splitter " (CSS), a "morphogenetic organ~lle " that we think may be responsible for the differentiation of ectoderm cells into neural plate and epidermis, in the embryonic ~lls of the axolotl. Ambystoma mexicanum (a urodele amphibian). The CSS consists of an apical microfilament (MF) ring, a lower intermediate filament~(IF) ring, and a subteliding. annular, nearly coplanar mat of apical microtubules (MT), all within I ~ of the apif,:alend of the 50-100 J.Un tall cells. Th ~ IF ring is attached to the membrane via desmosomes, and the MF ring and apical MTs, may be so attached. The CSS is constructed inectodenn celts between early and mid-gastrula, coincident with: '(I) high concentrati()ns C)fribosomes that are membrane associated and apically localized, (2) an increase in global tension of the embryo, and (3) a furrowing wave of surface contraction 'that passes over the pr...

Research paper thumbnail of Environmental genomics. Preface

Methods in molecular biology, 2008

Research paper thumbnail of DNA methyltransferase in the zebrafish Danio rerio: 5-aza-cytidine treatment of embryos in vivo causes disruption in the development of the axial mesoderm

I have conducted sequence analysis of a zebrafish cDNA that encodes the protein DNA (5-cytosine) ... more I have conducted sequence analysis of a zebrafish cDNA that encodes the protein DNA (5-cytosine) methyltransferase. I show that during development transcription of this zebrafish DNA methyltransferase gene is most high at blastula where it is ubiquitously expressed. At 24 hours of development, highest expression is observed in the brain, neural tube, eyes, and differentiating somites. To further assess the role of DNA methylation during development, I treated zebrafish embryos with 5-aza-cytidine (5-azaC), a nucleotide analog known to induce cellular differentiation and DNA hypomethylation in mammalian cell cultures. Treatments with 5-azaC during blastula and early gastrula caused a perturbation of the body axis resulting in loss of tail, and loss or abnormal development of the somites. Histological sections and in situ hybridization revealed whole or partial loss of a differentiated notochord and mid-line muscle in treated embryos. There was loss of expression of no tail in the notochord and eng in muscle-pioneer cells at 24 hours. When examined during gastrulation, 5-azaC treated embryos has a shortened and thickened axial mesoderm. DNA analysis on 5-azaC-treated embryos indicated an overall decrease in DNA methylation when compared to untreated controls. Embryos treated with 6-aza-cytidine, a cytidine analog not known to affect DNA methylation, showed neither abnormal development nor hypomethylation. Our findings suggest that normal DNA methylation is required for proper differentiation of dorsal mesoderm and pattern development of the dorsal-ventral body axis.

Research paper thumbnail of Not just a fishing trip-Environmental genomics using zebrafish

Research paper thumbnail of Not just a fishing trip—environmental genomics using zebrafish

Abstract: Genetic diversity is the raw material needed by a species allowing adaptation to changi... more Abstract: Genetic diversity is the raw material needed by a species allowing adaptation to changing environmental conditions and thus ensuring long-term sustainability. The development of technologies for environmental genomics provides us with the opportunity to link information, at the whole genome level, with the response of an organism to its natural environment. Over the past 15 years a small tropical fish native to the rivers of India and south Asia, the zebrafish (Danio rerio), has become one of the most popular vertebrate model systems. Zebrafish are abundant and many populations exist that are reproductively isolated. They evolved under distinct environments, and this have lead to genetic diversity and, as a consequence, has created genotypic and phenotypic differences between the populations. For this fish species, a large number of molecular and genomic tools have been developed. As a result, the zebrafish has emerged as a popular model for the study of embryonic developm...

Research paper thumbnail of Environmental genomics

... Methods in Lipid Membranes, edited by Alex Dopico, 2007 399. Neuroprotection Methods and Prot... more ... Methods in Lipid Membranes, edited by Alex Dopico, 2007 399. Neuroprotection Methods and Protocols, edited by Tiziana Borsello, 2007 398. Lipid Rafts, edited by Thomas J. McIntosh, 2007 397. Hedgehog Signaling Protocols, edited by Jamila I. Horabin, 2007 396. ...

Research paper thumbnail of The Evolution of Perception

Http Dx Doi Org 10 1080 01969720151033553, Oct 29, 2010

Research paper thumbnail of Environmental genomics. Preface

Methods in molecular biology (Clifton, N.J.), 2008

Research paper thumbnail of A role for modifier genes in genome imprinting

Results and problems in cell differentiation, 1999

Research paper thumbnail of High-throughput whole mount in situ hybridization of zebrafish embryos for analysis of tissue-specific gene expression changes after environmental perturbation

Methods in molecular biology (Clifton, N.J.), 2008

Whole mount in situ hybridization is a process that allows the visualization of gene expression (... more Whole mount in situ hybridization is a process that allows the visualization of gene expression (mRNA) within the cells of an intact organism. By comparing gene expression domains between organisms that have been subjected to different environmental conditions, an understanding of the cellular and tissue-specific effects of these environmental exposures can be identified. This technique is complementary to gene expression profiling techniques such as DNA microarrays which can usually provide information only on the differential levels of gene expression within an organism or tissue. In the case of whole mount in situ hybridization there is the added ability to detect differences in the distribution of cells, within a whole organism, expressing a particular gene. Subtle changes in the distribution of cells expressing a gene may not be reflected in the overall level of gene expression when RNA samples are retrieved from a whole organism and assayed. Exploitation of automation technolo...

Research paper thumbnail of Specific craniofacial cartilage dysmorphogenesis coincides with a loss of dlx gene expression in retinoic acid-treated zebrafish embryos

Mechanisms of Development, 1997

Treatments of zebrafish embryos with retinoic acid (RA), a substance known to cause abnormal cran... more Treatments of zebrafish embryos with retinoic acid (RA), a substance known to cause abnormal craniofacial cartilage development in other vertebrates, result in dose-and stage-dependent losses of dlx homeobox gene expression in several regions of the embryo. Dlx expression in neural crest cells migrating from the hindbrain and in the visceral arch primordia is particularly sensitive to RA treatment. The strongest effects are observed when RA is administered prior to or during crest cell migration but effects can also be observed if RA is applied when the cells have entered the primordia of the arches. Losses of dlx expression correlate either with the loss of cartilage elements originating from hindbrain neural crest cells or with abnormal morphology of these elements. Cartilage elements that originate from midbrain neural crest cells, which do not express dlx genes, are less affected. Taken together with the observation that the normal patterns of visceral arch dlx expression just prior to cartilage condensation resemble the morphology of the cartilage elements that are about to differentiate, our results suggest that dlx genes are an important part of a multi-step process in the development of a subset of craniofacial cartilage elements.

Research paper thumbnail of Furrowing surface contraction wave coincident with primary neural induction in amphibian embryos

Journal of Morphology, 1994

... Custom time-lapse and focus-collage software used in this project was devel-oped by Andrew Ma... more ... Custom time-lapse and focus-collage software used in this project was devel-oped by Andrew MacLean and Andrea Mar-tinko, Department of Civil Engineering, University of Waterloo. ... Markin, VS, VF Pastushenko, and YA Chizmadzhev (1987) Theory of Excitable Media. ...

Research paper thumbnail of Differentiation trees, a junk DNA molecular clock, and the evolution of neoteny in salamanders

Journal of Evolutionary Biology, 1995

Research paper thumbnail of Stable Transfer of Zebrafish Chromosome Segments into Mouse Cells

Genomics, 1996

Whole-cell fusion between zebrafish fibroblast-like tools such as a genetic linkage map and a phy... more Whole-cell fusion between zebrafish fibroblast-like tools such as a genetic linkage map and a physical map ZF4 cells and mouse B78 melanoma cells resulted in of overlapping YAC, P1, or cosmid clones will facilitate hybrids containing one or a few zebrafish chromosome the cloning of genes that are affected in zebrafish musegments in a murine chromosomal background. Fluotants. Recently, a genetic linkage map of the zebrafish rescence in situ hybridization to hybrid cell metagenome has been reported (Postlethwait et al., 1994). phases with a zebrafish genomic DNA probe revealed The map consists of more than 400 random amplified that many hybrids contained zebrafish chromosome polymorphic DNAs (RAPDs) (Williams et al., 1990; segments that were either inserted or translocated to a Welsh and McClelland, 1990). It was originally orgamouse chromosome, whereas other hybrids contained nized into 29 linkage groups but has now been consolizebrafish chromosomes with no evidence of insertion dated into 25 linkage groups (S. L. Johnson and J. Postor translocation. We have assigned hybrids to 17 linklethwait, unpublished data), corresponding to the numage groups of the genetic map of the zebrafish genome. ber of zebrafish chromosomes identified by karyotype Our results demonstrate the feasibility of producing (Schreeb et al., 1993). The map has been complemented somatic cell hybrids between distantly related species. by the integration of anonymous DNA markers based Zebrafish/mouse cell hybrids will provide a useful tool upon simple sequence repeats (SSRs) (Goff et al., 1992) for the physical mapping of the zebrafish genome and and of cloned genes (Postlethwait et al., 1994). The for the cloning of genes affected in zebrafish mutants. linkage map of the zebrafish genome will contribute to ᭧ 1996 Academic Press, Inc. the molecular analysis of zebrafish mutations affecting development. Panels of human/mouse and mouse/hamster somatic Whole-cell fusion. Calcium phosphate precipitation (Maniatis et al., 1989) was used to transfer the pCMV neo plasmid into ZF4 cells.

Research paper thumbnail of Expression and genomic organization of the zebrafish chaperonin gene complex

Genome, 2002

Chaperonin 10 and chaperonin 60 monomers exist within the multimeric mitochondrial chaperonin fol... more Chaperonin 10 and chaperonin 60 monomers exist within the multimeric mitochondrial chaperonin folding complex with a stoichiometry of 2:1. This complex is located in the mitochondrial matrix, where it aids in the folding and acquisition of the tertiary structure of proteins. We have previously isolated the cpn10 cDNA in zebrafish (Danio rerio), and demonstrated that it is ubiquitously expressed during embryonic development and transcriptionally upregulated after exposure to heat shock. In the present study, we have isolated a cDNA encoding chaperonin 60 (cpn60) from zebrafish, and have shown that it is similarly expressed uniformly and ubiquitously throughout early embryonic development of zebrafish. Upregulation of cpn60 expression was also observed after exposure of zebrafish embryos to a heat shock of 1 h at 37°C compared with control embryos raised at 27°C. The induction of the cpn60 heat shock response was greatest after 1 h of heat shock, whereas significant decreases of cpn60...

Research paper thumbnail of Genotype-specific modifiers of transgene methylation and expression in the zebrafish, Danio rerio

Genetical Research, 1995

SummaryPrevious reports involving mammalian systems, particularly mice, have demonstrated the exi... more SummaryPrevious reports involving mammalian systems, particularly mice, have demonstrated the existence of cis- and trans-acting modifiers of transgene methylation. These modifiers are thought to be important in dominance modification, genome imprinting and cellular expression mosaicism. Their potential role in the penetrance and severity of many complex human diseases could be of even greater significance. In the present investigation we demonstrate that modifiers that act in a similar fashion to those identified in mice also exist in a non-mammalian vertebrate, the zebrafish Danio rerio. We also provide evidence that the transgene methylation pattern may be influenced by the sex of the individual and environmental modulators such as temperature and sodium butyrate. These data support the theory that this type of dominance modification is mechanistically similar to position effect variegation in Drosophila. Furthermore, these data suggest evolutionary conservation of the modifiers,...

Research paper thumbnail of Parent-of-origin specific effects on the methylation of a transgene in the zebrafish,Danio rerio

Developmental Genetics, 1995

... The similarity be-tween this mosaic transgene expression in zebrafish and our previously desc... more ... The similarity be-tween this mosaic transgene expression in zebrafish and our previously described mosaic transgene expres-sion in mice [McGowan et al., 19891 raised the possi-bility of a similar imprinting system operating ... Address reprint requests to Ross McGowan, Dept. ...

Research paper thumbnail of Differential expression of the methyl-cytosine binding protein 2 gene in embryonic and adult brain of zebrafish

Developmental Brain Research, 2004

Epigenetic gene repression occurs as the result of the interactions between DNA and a number of p... more Epigenetic gene repression occurs as the result of the interactions between DNA and a number of proteins, including methyl-cytosine binding protein 2 (MeCP2). We have isolated a 1680 bps MeCP2 cDNA from zebrafish that shows deduced amino acid identity with Xenopus and mammalian MeCP2a protein sequences. The zebrafish MeCP2 gene was mapped to linkage group 8 using the LN54 radiation hybrid cell panel. The genomic organizations of the zebrafish MeCP2 and mammalian MeCP2a are highly similar. Relatively high levels of expression of MeCP2 mRNA were found in embryos at 1 to 4 h postfertilization (hpf), after 24 hpf, and in adult brain and eyes. Whole mount in situ hybridization was performed on embryos and revealed ubiquitous MeCP2 expression during early zebrafish development. At 24 and 48 hpf, the highest levels of expression are found in the epiphysis, midbrain, ventricular zone, and the otic vesicles. In adult zebrafish, MeCP2-expressing cells were found throughout the brain. Regions that are enriched in MeCP2 mRNA include the pallium layer of the telencephalon, the preoptic area, the periventricular grey zone, lobus caudalis, and the vagus lobes. In the cerebellum, high expression is found in the Purkinje and Golgi type 2 cells.

Research paper thumbnail of Disruption of Zebrafish Somite Development by Pharmacologic Inhibition of Hsp90

Developmental Biology, 1999

Members of the Hsp90 family of molecular chaperones play important roles in allowing some intrace... more Members of the Hsp90 family of molecular chaperones play important roles in allowing some intracellular signaling molecules and transcription factors to reach and maintain functionally active conformations. In the present study, we have utilized the specific Hsp90-binding agent, geldanamycin, to examine the requirement for Hsp90 during zebrafish development. We show that geldanamycin interacts with both the ␣ and the ␤-isoforms of zebrafish Hsp90 and that geldanamycin-treated embryos consistently exhibit a number of defects in tissues which express either one of these genes. Within the somites, geldanamycin treatment results in the absence of eng-2-expressing muscle pioneer cells. However, early development of adaxial cells, which give rise to muscle pioneers and which strongly express the hsp90␣ gene shortly before muscle pioneer formation, appeared unaffected. Furthermore, development of the notochord, which provides many of the signals required for proper somite patterning and which does not express detectable levels of either hsp90␣ or hsp90␤ mRNA, was similarly unaffected in geldanamycin-treated embryos. The data are consistent with there being a temporal and spatial requirement for Hsp90 function within somitic cells which is necessary for the formation of eng-2-expressing muscle pioneers and possibly other striated muscle fiber types.