Carl Schildkraut - Academia.edu (original) (raw)
Papers by Carl Schildkraut
Nucleic Acids Research, 1980
When mouse DNA is digested to completion with restriction endonuclease Eco Rl, a distinct band of... more When mouse DNA is digested to completion with restriction endonuclease Eco Rl, a distinct band of 1.3 kb segments comprising about 0.5-3% of thegenomeis observed upon agarose gel electrophoresis. This DNA is not tandemlyrepeated in the genome and is not derived from mouse satellite DNA. Restriction endonuclease analysis suggested that the 1.3 kb segments are heterogeneous. Specific sequences were selected from the 1.3 kb segments and amplified by cloning in plasmid pBR322. Southern transfer experiments indicated that three separately cloned mouse DNA inserts hybridized predominantly to the Eco R1 1.3 kbband and to the conspicuous subsegments generated by secondary restriction endonuclease cleavage of the sucrose gradient purified 1.3 kb segments. Segments were also excised by Hha I (Hha I segments) from the chimeric plasmids containing mouse DNA inserts and subjected to restriction endonuclease and cross-hybridization analysis. It was found that the three Hha I segments were different, although two of them exhibited partial sequence homology. Cot analysis indicated that each of the Hha I segments are repeated about 104 times in the mouse genome. These findings indicate that a family of related but non-identical, moderately repetitive DNA sequences, rather than a single homogeneous repeat, is present in the 1.3 kb Eco RI band.
Nucleic Acids Research, 1980
When mouse DNA is digested to completion with restriction endonuclease Eco Rl, a distinct band of... more When mouse DNA is digested to completion with restriction endonuclease Eco Rl, a distinct band of 1.3 kb segments comprising about 0.5-3% of thegenomeis observed upon agarose gel electrophoresis. This DNA is not tandemlyrepeated in the genome and is not derived from mouse satellite DNA. Restriction endonuclease analysis suggested that the 1.3 kb segments are heterogeneous. Specific sequences were selected from the 1.3 kb segments and amplified by cloning in plasmid pBR322. Southern transfer experiments indicated that three separately cloned mouse DNA inserts hybridized predominantly to the Eco R1 1.3 kbband and to the conspicuous subsegments generated by secondary restriction endonuclease cleavage of the sucrose gradient purified 1.3 kb segments. Segments were also excised by Hha I (Hha I segments) from the chimeric plasmids containing mouse DNA inserts and subjected to restriction endonuclease and cross-hybridization analysis. It was found that the three Hha I segments were different, although two of them exhibited partial sequence homology. Cot analysis indicated that each of the Hha I segments are repeated about 104 times in the mouse genome. These findings indicate that a family of related but non-identical, moderately repetitive DNA sequences, rather than a single homogeneous repeat, is present in the 1.3 kb Eco RI band.
Chromosoma, 1992
Cytogenetic techniques revealed an altered early replication banding pattern on the distal part o... more Cytogenetic techniques revealed an altered early replication banding pattern on the distal part of chromosome 15 in some murine T-cell lymphomas. This pattern reverted back to normal replication in somatic cell hybrids that had become non-tumorigenic after fusion of leukemic cells with normal fibroblasts. The altered banding pattern was correlated with malignancy. To investigate the molecular basis of the aberrant pattern in more detail, centrifugal elutriation of cells containing bromodeoxyuridine labeled DNA was used to prepare newly replicated DNA from selected intervals of the S-phase from tumor cells, as well as from hybrid cells with the revertant phenotype. These different DNA fractions were probed for DNA sequences distributed over the distal half of chromosome 15. Only two out of ten chromosome 15 specific genes tested showed a clear change in replication timing between the two different cell lines tested. These two genes were the lymphocyte antigen-6, Ly-6, and the neighboring thyroglobulin gene, Tgn, which replicated at the beginning of S in the tumor cells and later in S in the non-tumorigenic hybrid cells.
Chromosoma, 1992
Cytogenetic techniques revealed an altered early replication banding pattern on the distal part o... more Cytogenetic techniques revealed an altered early replication banding pattern on the distal part of chromosome 15 in some murine T-cell lymphomas. This pattern reverted back to normal replication in somatic cell hybrids that had become non-tumorigenic after fusion of leukemic cells with normal fibroblasts. The altered banding pattern was correlated with malignancy. To investigate the molecular basis of the aberrant pattern in more detail, centrifugal elutriation of cells containing bromodeoxyuridine labeled DNA was used to prepare newly replicated DNA from selected intervals of the S-phase from tumor cells, as well as from hybrid cells with the revertant phenotype. These different DNA fractions were probed for DNA sequences distributed over the distal half of chromosome 15. Only two out of ten chromosome 15 specific genes tested showed a clear change in replication timing between the two different cell lines tested. These two genes were the lymphocyte antigen-6, Ly-6, and the neighboring thyroglobulin gene, Tgn, which replicated at the beginning of S in the tumor cells and later in S in the non-tumorigenic hybrid cells.
Chromosoma, 1992
Cytogenetic techniques revealed an altered early replication banding pattern on the distal part o... more Cytogenetic techniques revealed an altered early replication banding pattern on the distal part of chromosome 15 in some murine T-cell lymphomas. This pattern reverted back to normal replication in somatic cell hybrids that had become non-tumorigenic after fusion of leukemic cells with normal fibroblasts. The altered banding pattern was correlated with malignancy. To investigate the molecular basis of the aberrant pattern in more detail, centrifugal elutriation of cells containing bromodeoxyuridine labeled DNA was used to prepare newly replicated DNA from selected intervals of the S-phase from tumor cells, as well as from hybrid cells with the revertant phenotype. These different DNA fractions were probed for DNA sequences distributed over the distal half of chromosome 15. Only two out of ten chromosome 15 specific genes tested showed a clear change in replication timing between the two different cell lines tested. These two genes were the lymphocyte antigen-6, Ly-6, and the neighboring thyroglobulin gene, Tgn, which replicated at the beginning of S in the tumor cells and later in S in the non-tumorigenic hybrid cells.
Biopolymers, 1965
... solved in different concentrations of KC1 are shown in Figure 1. The melting temperatures of ... more ... solved in different concentrations of KC1 are shown in Figure 1. The melting temperatures of all three DNA samples in KC1 solution obtained from such curves are summarized in Table I, which also includes the values for E. coli DNA in two buffered solutions. ...
Biopolymers, 1965
... solved in different concentrations of KC1 are shown in Figure 1. The melting temperatures of ... more ... solved in different concentrations of KC1 are shown in Figure 1. The melting temperatures of all three DNA samples in KC1 solution obtained from such curves are summarized in Table I, which also includes the values for E. coli DNA in two buffered solutions. ...
Biopolymers, 1965
... solved in different concentrations of KC1 are shown in Figure 1. The melting temperatures of ... more ... solved in different concentrations of KC1 are shown in Figure 1. The melting temperatures of all three DNA samples in KC1 solution obtained from such curves are summarized in Table I, which also includes the values for E. coli DNA in two buffered solutions. ...
Proceedings of the National Academy of Sciences of the United States of America, Jan 15, 2002
The 3' Ig heavy chain locus (Igh) regulatory region is the most downstream known element of t... more The 3' Ig heavy chain locus (Igh) regulatory region is the most downstream known element of the murine Igh gene cluster. We report here that the nearest non-Igh genes-Crip, Crp2, and Mta1-are located approximately 70 kb further downstream and are beyond the end of the domain of Igh transcriptional regulation. We have localized an origin of replication in MEL cells to a 3-kb segment located between the 3' Igh regulatory region and Crip. Sequences downstream of this origin are replicated by forks that move in both directions. Sequences upstream of this origin (Igh-C, -D, and -J) are replicated in a single direction through a 500-kb segment in which no active bidirectional origins can be detected. We propose that this origin may lie at or near the end of the Igh regulation domain.
Journal of Biological Chemistry
Journal of Molecular Biology
ABSTRACT
Molecular and Cellular Biology
The temporal order of replication of DNA sequences in the chromosomal domain containing the human... more The temporal order of replication of DNA sequences in the chromosomal domain containing the human j3-globin gene cluster and its flanking sequences (140 kilobases) was measured and compared in two different human cell lines. In human erythroleukemia (K562) cells, in which embryonic and fetal globin genes are transcribed, all of the sequences we examined from the P-globin domain replicated early during S phase, while in HeLa cells, in which globin genes are transcriptionally silent, these sequences replicated late during S. Potential sites of initiation of DNA replication within this domain were identified. The 3-globin gene domain was also found to differ with respect to the nuclease sensitivity of the chromatin in these two cell lines. In K562 cells, hypersensitive sites for endogenous nucleases and DNase I were present in the chromatin near the earliest-replicating segments in the 13-globin domain.
Molecular and Cellular Biology
To investigate whether a switch in the transcriptional activity of a gene is associated with a ch... more To investigate whether a switch in the transcriptional activity of a gene is associated with a change in the timing of replication during the S phase, we examined the replication timing of the I-globin genes in two different types of somatic cell hybrids. In mouse hepatoma (Hepa la) x mouse erythroleukemia (MEL) hybrid cells, the j8-globin gene from the MEL parent is transcriptionaily inactivated and is later replicating than in the parental MEL cell line. In human fibroblast (GM3552) x MEL hybrid cells, the human ,3-globin gene is transcriptionally activated, and all of the sequences within the human 0-globin domain (200 kilobases) we have examined appear to be earlier replicating than those in the parental fibroblast cell line. The chromatin configuration of the activated human 0-globin domain in the hybrids is relatively more sensitive to nucleases than that in the fibroblasts. Furthermore, major nuclease-hypersensitive sites that were absent in the chromatin flanking the distal 5' region of the human ,(-globin gene cluster in the parental fibroblast cell line are present in the transcriptionally activated domain in the hybrid cell line. These results suggest that timing of replication of globin genes has been altered in these hybrid cells and thus is not fixed during the process of differentiation.
Journal of Virology
DNA replication intermediates of three plasmids containing all or part of a modified Epstein-Barr... more DNA replication intermediates of three plasmids containing all or part of a modified Epstein-Barr virus cis-acting plasmid maintenance region (oriP) were examined to further investigate oriP function. Replication intermediates were analyzed in vivo and in vitro by neutral-neutral two-dimensional gel electrophoresis. The major functional components of the wild-type oriP are a 140-bp dyad symmetry region (single dyad) and 20 tandem copies of a repeat with a 30-bp consensus sequence (family of repeats). A modified oriP was constructed by replacing the family of repeats with three tandem copies of the single dyad (D. A. Wysokenski and J. L. Yates, J. Virol. 63:2657-2666. Initiation was observed in vivo near the single dyad in the modified oriP, as seen in the wild-type oriP (T. A. Gahn and C. L. Schildkraut, Cell 58:527-535, 1989), but was not observed near the tandem dyads. A replication barrier and termination were observed near the tandem dyads and were similar to those observed at the family of repeats of the wild-type oriP (Gahn and Schildkraut, Cell 58:527-535, 1989). In vitro experiments indicate that the viral trans-acting factor EBNA-1 contributes to efficient barrier formation at the tandem dyads as observed in the family of repeats of the wild-type oriP (V. Dhar and C. L.
In a subclone of 1ID13 mouse fibroblasts latently infected with bovine papillomavirus type 1 (BPV... more In a subclone of 1ID13 mouse fibroblasts latently infected with bovine papillomavirus type 1 (BPV-1) DNA, the viral genome occurred as a mixture of extrachromosomal circular monomers and oligomers. Multiple copies were also associated with the host cell genome, predominantly at a single site in a head-to-tail tandem array. We examined the replicative intermediates of extrachromosomal forms of BPV-1 DNA by using two-dimensional gel electrophoresis. The results obtained indicate that initiation of DNA replication occurred near the center of the EcoRI-BamHI 5.6-kilobase fragment. In some molecules, however, this fragment was replicated from one end to the other by means of a single fork initiated elsewhere. Termination also occurred within this fragment. The EcoRI-BamHI 2.3-kilobase fragment replicated as a DNA molecule containing a termination site for DNA replication and also by means of a single fork traversing the fragment from one end to the other. Thus, replication forks proceeded through these fragments in different manners, apparently depending on whether they were part of a monomer, a d'imer, a trimer, or higher oligomers. These observations lead to the conclusion that initiation of DNA replication in BPV-1 DNA takes place at or close to plasmid maintenance sequence 1. From this point, replication proceeds bidirectionally and termination occurs approximately 1800 opposite the origin. The results obtained are consistent with one or more replication origins being quiescent in BPV-1 DNA oligomers.
Nucleic Acids Research, 1980
When mouse DNA is digested to completion with restriction endonuclease Eco Rl, a distinct band of... more When mouse DNA is digested to completion with restriction endonuclease Eco Rl, a distinct band of 1.3 kb segments comprising about 0.5-3% of thegenomeis observed upon agarose gel electrophoresis. This DNA is not tandemlyrepeated in the genome and is not derived from mouse satellite DNA. Restriction endonuclease analysis suggested that the 1.3 kb segments are heterogeneous. Specific sequences were selected from the 1.3 kb segments and amplified by cloning in plasmid pBR322. Southern transfer experiments indicated that three separately cloned mouse DNA inserts hybridized predominantly to the Eco R1 1.3 kbband and to the conspicuous subsegments generated by secondary restriction endonuclease cleavage of the sucrose gradient purified 1.3 kb segments. Segments were also excised by Hha I (Hha I segments) from the chimeric plasmids containing mouse DNA inserts and subjected to restriction endonuclease and cross-hybridization analysis. It was found that the three Hha I segments were different, although two of them exhibited partial sequence homology. Cot analysis indicated that each of the Hha I segments are repeated about 104 times in the mouse genome. These findings indicate that a family of related but non-identical, moderately repetitive DNA sequences, rather than a single homogeneous repeat, is present in the 1.3 kb Eco RI band.
Nucleic Acids Research, 1980
When mouse DNA is digested to completion with restriction endonuclease Eco Rl, a distinct band of... more When mouse DNA is digested to completion with restriction endonuclease Eco Rl, a distinct band of 1.3 kb segments comprising about 0.5-3% of thegenomeis observed upon agarose gel electrophoresis. This DNA is not tandemlyrepeated in the genome and is not derived from mouse satellite DNA. Restriction endonuclease analysis suggested that the 1.3 kb segments are heterogeneous. Specific sequences were selected from the 1.3 kb segments and amplified by cloning in plasmid pBR322. Southern transfer experiments indicated that three separately cloned mouse DNA inserts hybridized predominantly to the Eco R1 1.3 kbband and to the conspicuous subsegments generated by secondary restriction endonuclease cleavage of the sucrose gradient purified 1.3 kb segments. Segments were also excised by Hha I (Hha I segments) from the chimeric plasmids containing mouse DNA inserts and subjected to restriction endonuclease and cross-hybridization analysis. It was found that the three Hha I segments were different, although two of them exhibited partial sequence homology. Cot analysis indicated that each of the Hha I segments are repeated about 104 times in the mouse genome. These findings indicate that a family of related but non-identical, moderately repetitive DNA sequences, rather than a single homogeneous repeat, is present in the 1.3 kb Eco RI band.
Chromosoma, 1992
Cytogenetic techniques revealed an altered early replication banding pattern on the distal part o... more Cytogenetic techniques revealed an altered early replication banding pattern on the distal part of chromosome 15 in some murine T-cell lymphomas. This pattern reverted back to normal replication in somatic cell hybrids that had become non-tumorigenic after fusion of leukemic cells with normal fibroblasts. The altered banding pattern was correlated with malignancy. To investigate the molecular basis of the aberrant pattern in more detail, centrifugal elutriation of cells containing bromodeoxyuridine labeled DNA was used to prepare newly replicated DNA from selected intervals of the S-phase from tumor cells, as well as from hybrid cells with the revertant phenotype. These different DNA fractions were probed for DNA sequences distributed over the distal half of chromosome 15. Only two out of ten chromosome 15 specific genes tested showed a clear change in replication timing between the two different cell lines tested. These two genes were the lymphocyte antigen-6, Ly-6, and the neighboring thyroglobulin gene, Tgn, which replicated at the beginning of S in the tumor cells and later in S in the non-tumorigenic hybrid cells.
Chromosoma, 1992
Cytogenetic techniques revealed an altered early replication banding pattern on the distal part o... more Cytogenetic techniques revealed an altered early replication banding pattern on the distal part of chromosome 15 in some murine T-cell lymphomas. This pattern reverted back to normal replication in somatic cell hybrids that had become non-tumorigenic after fusion of leukemic cells with normal fibroblasts. The altered banding pattern was correlated with malignancy. To investigate the molecular basis of the aberrant pattern in more detail, centrifugal elutriation of cells containing bromodeoxyuridine labeled DNA was used to prepare newly replicated DNA from selected intervals of the S-phase from tumor cells, as well as from hybrid cells with the revertant phenotype. These different DNA fractions were probed for DNA sequences distributed over the distal half of chromosome 15. Only two out of ten chromosome 15 specific genes tested showed a clear change in replication timing between the two different cell lines tested. These two genes were the lymphocyte antigen-6, Ly-6, and the neighboring thyroglobulin gene, Tgn, which replicated at the beginning of S in the tumor cells and later in S in the non-tumorigenic hybrid cells.
Chromosoma, 1992
Cytogenetic techniques revealed an altered early replication banding pattern on the distal part o... more Cytogenetic techniques revealed an altered early replication banding pattern on the distal part of chromosome 15 in some murine T-cell lymphomas. This pattern reverted back to normal replication in somatic cell hybrids that had become non-tumorigenic after fusion of leukemic cells with normal fibroblasts. The altered banding pattern was correlated with malignancy. To investigate the molecular basis of the aberrant pattern in more detail, centrifugal elutriation of cells containing bromodeoxyuridine labeled DNA was used to prepare newly replicated DNA from selected intervals of the S-phase from tumor cells, as well as from hybrid cells with the revertant phenotype. These different DNA fractions were probed for DNA sequences distributed over the distal half of chromosome 15. Only two out of ten chromosome 15 specific genes tested showed a clear change in replication timing between the two different cell lines tested. These two genes were the lymphocyte antigen-6, Ly-6, and the neighboring thyroglobulin gene, Tgn, which replicated at the beginning of S in the tumor cells and later in S in the non-tumorigenic hybrid cells.
Biopolymers, 1965
... solved in different concentrations of KC1 are shown in Figure 1. The melting temperatures of ... more ... solved in different concentrations of KC1 are shown in Figure 1. The melting temperatures of all three DNA samples in KC1 solution obtained from such curves are summarized in Table I, which also includes the values for E. coli DNA in two buffered solutions. ...
Biopolymers, 1965
... solved in different concentrations of KC1 are shown in Figure 1. The melting temperatures of ... more ... solved in different concentrations of KC1 are shown in Figure 1. The melting temperatures of all three DNA samples in KC1 solution obtained from such curves are summarized in Table I, which also includes the values for E. coli DNA in two buffered solutions. ...
Biopolymers, 1965
... solved in different concentrations of KC1 are shown in Figure 1. The melting temperatures of ... more ... solved in different concentrations of KC1 are shown in Figure 1. The melting temperatures of all three DNA samples in KC1 solution obtained from such curves are summarized in Table I, which also includes the values for E. coli DNA in two buffered solutions. ...
Proceedings of the National Academy of Sciences of the United States of America, Jan 15, 2002
The 3' Ig heavy chain locus (Igh) regulatory region is the most downstream known element of t... more The 3' Ig heavy chain locus (Igh) regulatory region is the most downstream known element of the murine Igh gene cluster. We report here that the nearest non-Igh genes-Crip, Crp2, and Mta1-are located approximately 70 kb further downstream and are beyond the end of the domain of Igh transcriptional regulation. We have localized an origin of replication in MEL cells to a 3-kb segment located between the 3' Igh regulatory region and Crip. Sequences downstream of this origin are replicated by forks that move in both directions. Sequences upstream of this origin (Igh-C, -D, and -J) are replicated in a single direction through a 500-kb segment in which no active bidirectional origins can be detected. We propose that this origin may lie at or near the end of the Igh regulation domain.
Journal of Biological Chemistry
Journal of Molecular Biology
ABSTRACT
Molecular and Cellular Biology
The temporal order of replication of DNA sequences in the chromosomal domain containing the human... more The temporal order of replication of DNA sequences in the chromosomal domain containing the human j3-globin gene cluster and its flanking sequences (140 kilobases) was measured and compared in two different human cell lines. In human erythroleukemia (K562) cells, in which embryonic and fetal globin genes are transcribed, all of the sequences we examined from the P-globin domain replicated early during S phase, while in HeLa cells, in which globin genes are transcriptionally silent, these sequences replicated late during S. Potential sites of initiation of DNA replication within this domain were identified. The 3-globin gene domain was also found to differ with respect to the nuclease sensitivity of the chromatin in these two cell lines. In K562 cells, hypersensitive sites for endogenous nucleases and DNase I were present in the chromatin near the earliest-replicating segments in the 13-globin domain.
Molecular and Cellular Biology
To investigate whether a switch in the transcriptional activity of a gene is associated with a ch... more To investigate whether a switch in the transcriptional activity of a gene is associated with a change in the timing of replication during the S phase, we examined the replication timing of the I-globin genes in two different types of somatic cell hybrids. In mouse hepatoma (Hepa la) x mouse erythroleukemia (MEL) hybrid cells, the j8-globin gene from the MEL parent is transcriptionaily inactivated and is later replicating than in the parental MEL cell line. In human fibroblast (GM3552) x MEL hybrid cells, the human ,3-globin gene is transcriptionally activated, and all of the sequences within the human 0-globin domain (200 kilobases) we have examined appear to be earlier replicating than those in the parental fibroblast cell line. The chromatin configuration of the activated human 0-globin domain in the hybrids is relatively more sensitive to nucleases than that in the fibroblasts. Furthermore, major nuclease-hypersensitive sites that were absent in the chromatin flanking the distal 5' region of the human ,(-globin gene cluster in the parental fibroblast cell line are present in the transcriptionally activated domain in the hybrid cell line. These results suggest that timing of replication of globin genes has been altered in these hybrid cells and thus is not fixed during the process of differentiation.
Journal of Virology
DNA replication intermediates of three plasmids containing all or part of a modified Epstein-Barr... more DNA replication intermediates of three plasmids containing all or part of a modified Epstein-Barr virus cis-acting plasmid maintenance region (oriP) were examined to further investigate oriP function. Replication intermediates were analyzed in vivo and in vitro by neutral-neutral two-dimensional gel electrophoresis. The major functional components of the wild-type oriP are a 140-bp dyad symmetry region (single dyad) and 20 tandem copies of a repeat with a 30-bp consensus sequence (family of repeats). A modified oriP was constructed by replacing the family of repeats with three tandem copies of the single dyad (D. A. Wysokenski and J. L. Yates, J. Virol. 63:2657-2666. Initiation was observed in vivo near the single dyad in the modified oriP, as seen in the wild-type oriP (T. A. Gahn and C. L. Schildkraut, Cell 58:527-535, 1989), but was not observed near the tandem dyads. A replication barrier and termination were observed near the tandem dyads and were similar to those observed at the family of repeats of the wild-type oriP (Gahn and Schildkraut, Cell 58:527-535, 1989). In vitro experiments indicate that the viral trans-acting factor EBNA-1 contributes to efficient barrier formation at the tandem dyads as observed in the family of repeats of the wild-type oriP (V. Dhar and C. L.
In a subclone of 1ID13 mouse fibroblasts latently infected with bovine papillomavirus type 1 (BPV... more In a subclone of 1ID13 mouse fibroblasts latently infected with bovine papillomavirus type 1 (BPV-1) DNA, the viral genome occurred as a mixture of extrachromosomal circular monomers and oligomers. Multiple copies were also associated with the host cell genome, predominantly at a single site in a head-to-tail tandem array. We examined the replicative intermediates of extrachromosomal forms of BPV-1 DNA by using two-dimensional gel electrophoresis. The results obtained indicate that initiation of DNA replication occurred near the center of the EcoRI-BamHI 5.6-kilobase fragment. In some molecules, however, this fragment was replicated from one end to the other by means of a single fork initiated elsewhere. Termination also occurred within this fragment. The EcoRI-BamHI 2.3-kilobase fragment replicated as a DNA molecule containing a termination site for DNA replication and also by means of a single fork traversing the fragment from one end to the other. Thus, replication forks proceeded through these fragments in different manners, apparently depending on whether they were part of a monomer, a d'imer, a trimer, or higher oligomers. These observations lead to the conclusion that initiation of DNA replication in BPV-1 DNA takes place at or close to plasmid maintenance sequence 1. From this point, replication proceeds bidirectionally and termination occurs approximately 1800 opposite the origin. The results obtained are consistent with one or more replication origins being quiescent in BPV-1 DNA oligomers.