Viviana Nuñez - Academia.edu (original) (raw)

Papers by Viviana Nuñez

Research paper thumbnail of Whole Tribolium castaneum embryo culture gives insights into the role of FGF signaling pathway during body segmentation in arthropods

Research paper thumbnail of Wnt pathway is involved in Tribolium castaneum segmentation and germband elongation

Research paper thumbnail of Tribolium castaneum whole embryo culture gives insights into the molecular mechanisms and cell dynamics during body segmentation in arthropods

Research paper thumbnail of Dissecting the segmentation process: A whole embryo culture approach to understand body segmentation in the beetle Tribolium castaneum

Research paper thumbnail of Signaling pathways involved in Tribolium castaneum gene oscillation-dependent germband elongation

Research paper thumbnail of Wnt signaling in the processes of segmentation and elongation in the beetle Tribolium castaneum

Research paper thumbnail of A Tribolium castaneum whole-embryo culture protocol for studying the molecular mechanisms and morphogenetic movements involved in insect development

Development Genes and Evolution, 2016

The development of the red flour beetle Tribolium castaneum is more representative of arthropods ... more The development of the red flour beetle Tribolium castaneum is more representative of arthropods than the evolutionarily derived fly, Drosophila melanogaster. Thus, Tribolium is becoming an emerging organism model for studying the evolution of the mechanisms that control embryonic development in arthropods. In this regard, diverse genetic and molecular tools are currently available for Tribolium, as well as imaging and embryonic techniques. Recently, we developed a method for culturing embryos in order to study specific stages during Tribolium development. In this report, we present a detailed and "easy-to-follow" protocol for embryo handling and dissection, extending the use of whole-embryo culture to functional analysis by performing in vivo pharmacological manipulations. This experimental accessibility allowed us to study the relevance of microtubules in axis elongation, using nocodazole and taxol drugs to interfere with microtubule networks, followed by length measurement analysis. Additionally, we demonstrated that embryo handling had no effect on the development of Tribolium embryos, and we checked viability after dissection and bisection and during incubation using propidium iodide. The embryo culture protocol we describe here can be applied to study diverse developmental processes in Tribolium. We expect that this protocol can be adapted and applied to other arthropods.

Research paper thumbnail of Proneural gene requirement for hair cell differentiation in the zebrafish lateral line

Developmental Biology, 2006

The lateral line system comprises an array of mechanosensory organs, the neuromasts, distributed ... more The lateral line system comprises an array of mechanosensory organs, the neuromasts, distributed over the body surface. Each neuromast consists of a patch of mechanosensory hair cells surrounded by support cells. We show that, in the zebrafish, two proneural genes are essential for differentiation of the hair cells, neuroD (nrd) and atonal homolog 1 (ath1). Gene knockdown experiments demonstrate that loss of function of either gene, but not of the related proneural gene neurogenin1 (ngn1), abrogate the appearance of hair cell markers. This is in contrast to other sensory systems, such as the neurons of the lateral line ganglion, where nrd is regulated by ngn1 and not by ath1. Overexpression of ath1 can induce nrd, and the phenotype produced by loss of ath1 function can be partially rescued by injection of nrd mRNA. This supports the conclusion that the activation of nrd probably requires ath1 in the hair cell lineage, whereas in sensory neurons nrd activation requires ngn1. We propose that the emergence of two atonal homologs, ath1 and ngn1, allowed the cellular segregation of mechanoreception and signal transmission that were originally performed by a single cell type as found in insects.

Research paper thumbnail of Development and regeneration in the zebrafish lateral line

Developmental Biology, 2007

Research paper thumbnail of Origin and Early Development of the Posterior Lateral Line System of Zebrafish

Journal of Neuroscience, 2010

The lateral line system of teleosts has recently become a model system to study patterning and mo... more The lateral line system of teleosts has recently become a model system to study patterning and morphogenesis. However, its embryonic origins are still not well understood. In zebrafish, the posterior lateral line (PLL) system is formed in two waves, one that generates the embryonic line of seven to eight neuromasts and 20 afferent neurons and a second one that generates three additional lines during larval development. The embryonic line originates from a postotic placode that produces both a migrating sensory primordium and afferent neurons. Nothing is known about the origin and innervation of the larval lines. Here we show that a "secondary" placode can be detected at 24 h postfertilization (hpf), shortly after the primary placode has given rise to the embryonic primordium and ganglion. The secondary placode generates two additional sensory primordia, primD and primII, as well as afferent neurons. The primary and secondary placodes require retinoic acid signaling at the same stage of late gastrulation, suggesting that they share a common origin. Neither primary nor secondary neurons show intrinsic specificity for neuromasts derived from their own placode, but the sequence of neuromast deposition ensures that neuromasts are primarily innervated by neurons derived from the cognate placode. The delayed formation of secondary afferent neurons accounts for the capability of the fish to form a new PLL ganglion after ablation of the embryonic ganglion at 24 hpf.

Research paper thumbnail of Postembryonic development of the posterior lateral line in the zebrafish

Evolution & Development, 2009

Research paper thumbnail of A whole embryo culture approach to study signaling pathways and cellular processes involved in Tribolium castaneum sequential segmentation

Research paper thumbnail of Sox2 and Sox3 are essential for development and regeneration of the zebrafish lateral line

ABSTRACTThe recovery of injured or lost sensory neurons after trauma, disease or aging is a major... more ABSTRACTThe recovery of injured or lost sensory neurons after trauma, disease or aging is a major scientific challenge. Upon hearing loss or balance disorder, regeneration of mechanosensory hair cells has been observed in fish, some amphibians and under special circumstances in birds, but is absent in adult mammals. In aquatic vertebrates, hair cells are not only present in the inner ear but also in neuromasts of the lateral line system. The zebrafish lateral line neuromast has an almost unlimited capacity to regenerate hair cells. This remarkable ability is possible due to the presence of neural stem/progenitor cells within neuromasts. In order to further characterize these stem cells, we use the expression of the neural progenitor markers Sox2 and Sox3, transgenic reporter lines, and morphological and topological analysis of the different cell types within the neuromast. We reveal new sub-populations of supporting cells, the sustentacular supporting cells and the neuromast stem ce...

Research paper thumbnail of Development Genes and Evolution A Tribolium castaneum whole-embryo culture protocol for studying the molecular mechanisms and morphogenetic movements involved in insect development

Your article is protected by copyright and all rights are held exclusively by Springer-Verlag Ber... more Your article is protected by copyright and all rights are held exclusively by Springer-Verlag Berlin Heidelberg. This e-offprint is for personal use only and shall not be selfarchived in electronic repositories. If you wish to self-archive your article, please use the accepted manuscript version for posting on your own website. You may further deposit the accepted manuscript version in any repository, provided it is only made publicly available 12 months after official publication or later and provided acknowledgement is given to the original source of publication and a link is inserted to the published article on Springer's website. The link must be accompanied by the following text: "The final publication is available at link.springer.com".

Research paper thumbnail of Whole Tribolium castaneum embryo culture gives insights into the role of FGF signaling pathway during body segmentation in arthropods

Research paper thumbnail of Wnt pathway is involved in Tribolium castaneum segmentation and germband elongation

Research paper thumbnail of Tribolium castaneum whole embryo culture gives insights into the molecular mechanisms and cell dynamics during body segmentation in arthropods

Research paper thumbnail of Dissecting the segmentation process: A whole embryo culture approach to understand body segmentation in the beetle Tribolium castaneum

Research paper thumbnail of Signaling pathways involved in Tribolium castaneum gene oscillation-dependent germband elongation

Research paper thumbnail of Wnt signaling in the processes of segmentation and elongation in the beetle Tribolium castaneum

Research paper thumbnail of A Tribolium castaneum whole-embryo culture protocol for studying the molecular mechanisms and morphogenetic movements involved in insect development

Development Genes and Evolution, 2016

The development of the red flour beetle Tribolium castaneum is more representative of arthropods ... more The development of the red flour beetle Tribolium castaneum is more representative of arthropods than the evolutionarily derived fly, Drosophila melanogaster. Thus, Tribolium is becoming an emerging organism model for studying the evolution of the mechanisms that control embryonic development in arthropods. In this regard, diverse genetic and molecular tools are currently available for Tribolium, as well as imaging and embryonic techniques. Recently, we developed a method for culturing embryos in order to study specific stages during Tribolium development. In this report, we present a detailed and "easy-to-follow" protocol for embryo handling and dissection, extending the use of whole-embryo culture to functional analysis by performing in vivo pharmacological manipulations. This experimental accessibility allowed us to study the relevance of microtubules in axis elongation, using nocodazole and taxol drugs to interfere with microtubule networks, followed by length measurement analysis. Additionally, we demonstrated that embryo handling had no effect on the development of Tribolium embryos, and we checked viability after dissection and bisection and during incubation using propidium iodide. The embryo culture protocol we describe here can be applied to study diverse developmental processes in Tribolium. We expect that this protocol can be adapted and applied to other arthropods.

Research paper thumbnail of Proneural gene requirement for hair cell differentiation in the zebrafish lateral line

Developmental Biology, 2006

The lateral line system comprises an array of mechanosensory organs, the neuromasts, distributed ... more The lateral line system comprises an array of mechanosensory organs, the neuromasts, distributed over the body surface. Each neuromast consists of a patch of mechanosensory hair cells surrounded by support cells. We show that, in the zebrafish, two proneural genes are essential for differentiation of the hair cells, neuroD (nrd) and atonal homolog 1 (ath1). Gene knockdown experiments demonstrate that loss of function of either gene, but not of the related proneural gene neurogenin1 (ngn1), abrogate the appearance of hair cell markers. This is in contrast to other sensory systems, such as the neurons of the lateral line ganglion, where nrd is regulated by ngn1 and not by ath1. Overexpression of ath1 can induce nrd, and the phenotype produced by loss of ath1 function can be partially rescued by injection of nrd mRNA. This supports the conclusion that the activation of nrd probably requires ath1 in the hair cell lineage, whereas in sensory neurons nrd activation requires ngn1. We propose that the emergence of two atonal homologs, ath1 and ngn1, allowed the cellular segregation of mechanoreception and signal transmission that were originally performed by a single cell type as found in insects.

Research paper thumbnail of Development and regeneration in the zebrafish lateral line

Developmental Biology, 2007

Research paper thumbnail of Origin and Early Development of the Posterior Lateral Line System of Zebrafish

Journal of Neuroscience, 2010

The lateral line system of teleosts has recently become a model system to study patterning and mo... more The lateral line system of teleosts has recently become a model system to study patterning and morphogenesis. However, its embryonic origins are still not well understood. In zebrafish, the posterior lateral line (PLL) system is formed in two waves, one that generates the embryonic line of seven to eight neuromasts and 20 afferent neurons and a second one that generates three additional lines during larval development. The embryonic line originates from a postotic placode that produces both a migrating sensory primordium and afferent neurons. Nothing is known about the origin and innervation of the larval lines. Here we show that a "secondary" placode can be detected at 24 h postfertilization (hpf), shortly after the primary placode has given rise to the embryonic primordium and ganglion. The secondary placode generates two additional sensory primordia, primD and primII, as well as afferent neurons. The primary and secondary placodes require retinoic acid signaling at the same stage of late gastrulation, suggesting that they share a common origin. Neither primary nor secondary neurons show intrinsic specificity for neuromasts derived from their own placode, but the sequence of neuromast deposition ensures that neuromasts are primarily innervated by neurons derived from the cognate placode. The delayed formation of secondary afferent neurons accounts for the capability of the fish to form a new PLL ganglion after ablation of the embryonic ganglion at 24 hpf.

Research paper thumbnail of Postembryonic development of the posterior lateral line in the zebrafish

Evolution & Development, 2009

Research paper thumbnail of A whole embryo culture approach to study signaling pathways and cellular processes involved in Tribolium castaneum sequential segmentation

Research paper thumbnail of Sox2 and Sox3 are essential for development and regeneration of the zebrafish lateral line

ABSTRACTThe recovery of injured or lost sensory neurons after trauma, disease or aging is a major... more ABSTRACTThe recovery of injured or lost sensory neurons after trauma, disease or aging is a major scientific challenge. Upon hearing loss or balance disorder, regeneration of mechanosensory hair cells has been observed in fish, some amphibians and under special circumstances in birds, but is absent in adult mammals. In aquatic vertebrates, hair cells are not only present in the inner ear but also in neuromasts of the lateral line system. The zebrafish lateral line neuromast has an almost unlimited capacity to regenerate hair cells. This remarkable ability is possible due to the presence of neural stem/progenitor cells within neuromasts. In order to further characterize these stem cells, we use the expression of the neural progenitor markers Sox2 and Sox3, transgenic reporter lines, and morphological and topological analysis of the different cell types within the neuromast. We reveal new sub-populations of supporting cells, the sustentacular supporting cells and the neuromast stem ce...

Research paper thumbnail of Development Genes and Evolution A Tribolium castaneum whole-embryo culture protocol for studying the molecular mechanisms and morphogenetic movements involved in insect development

Your article is protected by copyright and all rights are held exclusively by Springer-Verlag Ber... more Your article is protected by copyright and all rights are held exclusively by Springer-Verlag Berlin Heidelberg. This e-offprint is for personal use only and shall not be selfarchived in electronic repositories. If you wish to self-archive your article, please use the accepted manuscript version for posting on your own website. You may further deposit the accepted manuscript version in any repository, provided it is only made publicly available 12 months after official publication or later and provided acknowledgement is given to the original source of publication and a link is inserted to the published article on Springer's website. The link must be accompanied by the following text: "The final publication is available at link.springer.com".