TY - JOUR
T1 - Allele-specific replication timing in imprinted domains
T2 - Absence of asynchrony at several loci
AU - Kawame, Hiroshi
AU - Gartler, Stanley M.
AU - Hansen, R. Scott
N1 - Funding Information:
Theresa Canfield and Alan Fjeld provided excellent technical assistance in some of the replication experiments. S.Chong Kim performed the flow cytometry fractionation of cells. We thank Lester Goldstein and Karen Dyer for helpful comments on the manuscript. H.K. was supported by a Uehara Memorial Foundation Postdoctoral Fellowship. Additional support was provided by National Institutes of Health Grant HDI6659 and American Cancer Society Grant IRG-184A.
PY - 1995/12
Y1 - 1995/12
N2 - Using a bromodeoxyuridine incorporation method to detect replicated DNA, we studied allele-specific replication for several sites within the human Prader-Willi/Angelman and IGF2/H19 imprinted regions. No obvious allele-specific differences in time of replication were detected at most loci previously reported to replicate asynchronously in the same cell types as determined by a FISH-based replication assay. Our finding of an absence of allelic replication asynchrony may be related to low levels of imprinted gene expression near these loci in the examined cells (lymphocytes, fibroblasts and lymphoblastoid cells). This view is supported by our studies of the imprinted SNRPN gene in that cells with paternal allele-specific expression (lymphocytes and lymphoblasts) replicate SNRPN alleles asynchronously, whereas cells with a low level of expression (HeLa) replicate SNRPN later and with less allelic asynchrony. In lymphoblasts, the early-replicating allele of SNRPN was identified as the paternal one based on the properties of maternal allele-specific methylation and paternal allele-specific expression. Our studies suggest that FISH data implying replication asynchrony in nonexpressing cells reflect structural differences between the maternal and paternal alleles rather than differences in replication timing.
AB - Using a bromodeoxyuridine incorporation method to detect replicated DNA, we studied allele-specific replication for several sites within the human Prader-Willi/Angelman and IGF2/H19 imprinted regions. No obvious allele-specific differences in time of replication were detected at most loci previously reported to replicate asynchronously in the same cell types as determined by a FISH-based replication assay. Our finding of an absence of allelic replication asynchrony may be related to low levels of imprinted gene expression near these loci in the examined cells (lymphocytes, fibroblasts and lymphoblastoid cells). This view is supported by our studies of the imprinted SNRPN gene in that cells with paternal allele-specific expression (lymphocytes and lymphoblasts) replicate SNRPN alleles asynchronously, whereas cells with a low level of expression (HeLa) replicate SNRPN later and with less allelic asynchrony. In lymphoblasts, the early-replicating allele of SNRPN was identified as the paternal one based on the properties of maternal allele-specific methylation and paternal allele-specific expression. Our studies suggest that FISH data implying replication asynchrony in nonexpressing cells reflect structural differences between the maternal and paternal alleles rather than differences in replication timing.
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U2 - 10.1093/hmg/4.12.2287
DO - 10.1093/hmg/4.12.2287
M3 - Article
C2 - 8634700
AN - SCOPUS:0028879861
VL - 4
SP - 2287
EP - 2293
JO - Human Molecular Genetics
JF - Human Molecular Genetics
SN - 0964-6906
IS - 12
ER -