Cell-type-specific expression of mouse DNA polymerase beta-gene is regulated by silencer elements.
RNA blot hybridization analysis revealed that the steady-state level of DNA polymerase beta-mRNA in mouse neuroblastoma N18TG2 cells was approximately five-fold higher than that in NIH/3T3 cells. In order to examine the function of DNA polymerase beta-gene silencers in these two cell lines, we employed a chloramphenicol acetyltransferase (CAT)-transient expression assay using the CAT plasmids containing the silencers linked to various promoter-enhancers. In NIH/3T3 cells, DNA polymerase beta-gene silencers effectively repressed the function of its own promoter and those of several other heterologous promoter-enhancers. In contrast, the silencers only marginally affected the CAT expression directed by DNA polymerase beta-gene promoter and heterologous promoter-enhancers in N18TG2 cells. The extent of the increase of CAT expression by removing silencer elements in NIH/3T3 cells was very similar to the ratio of DNA polymerase beta-mRNA content in N18TG2 cells to that in NIH/3T3 cells. These results indicate that cell-type-specific expression of DNA polymerase beta-gene is primarily controlled by the function of its silencer elements.
Yamaguchi
M
M
Laboratory of Cell Biology, Aichi Cancer Center Research Institute, Nagoya, Japan.
Hayashi
Y
Y
Ajiro
K
K
Matsukage
A
A
D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D004256:DNA Polymerase I / Q000032:analysis / Q000235:genetics* / Q000502:physiology; D005347:Fibroblasts / Q000166:cytology* / Q000378:metabolism; D015870:Gene Expression; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D051379:Mice; D008815:Mice, Inbred Strains; D009447:Neuroblastoma / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014407:Tumor Cells, Cultured / Q000378:metabolism / Q000473:pathology
D012333:RNA, Messenger; D004256:DNA Polymerase I