Analysis of EPC-1 growth state-dependent expression, specificity, and conservation of related sequences.
The transcript for EPC-1 (early population doubling level (PDL) cDNA-1) is induced under conditions of growth arrest due to density-dependent contact inhibition and/or serum deprivation in early-passage but not in senescent WI-38 fibroblasts. We have characterized the EPC-1 transcript with respect to its cell-cycle regulation, tissue specificity, and interspecies conservation of related genomic sequences. In low density, quiescent (serum-deprived), early-passage fibroblasts that are stimulated to proliferate with fresh serum, steady-state EPC-1 transcript levels are steadily reduced until they reach a basal level approximately 24 h after stimulation. However, when early-passage fibroblasts are made quiescent by both serum deprivation and density-dependent contact inhibition and then stimulated with serum, steady-state EPC-1 transcript levels remain relatively constant throughout a 36 h period following serum stimulation. Senescent WI-38 cells (> 95% life span completed) do not express EPC-1 under these conditions. We show that differences in the regulation of EPC-1 transcript levels in early-passage cells are due to differences in growth state rather than changes in cell density or contact. We also show that expression of the EPC-1 transcript is limited to specific cell types and that related genomic sequences are found in all mammalian species examined as well as in the chicken.
Pignolo
R J
RJ
Center for Gerontological Research, Medical College of Pennsylvania, Philadelphia 19129.
Rotenberg
M O
MO
Cristofalo
V J
VJ
D015152:Blotting, Northern; D002450:Cell Communication / Q000502:physiology; D002452:Cell Count; D002453:Cell Cycle / Q000502:physiology; D002460:Cell Line; D018076:DNA, Complementary / Q000032:analysis / Q000235:genetics*; D005136:Eye Proteins; D005347:Fibroblasts / Q000737:chemistry* / Q000166:cytology* / Q000502:physiology; D005786:Gene Expression Regulation; D006801:Humans; D009414:Nerve Growth Factors; D011506:Proteins / Q000737:chemistry / Q000235:genetics*; D015843:Serpins / Q000737:chemistry / Q000235:genetics*; D014158:Transcription, Genetic; D000099174:Pigment Epithelium-Derived Factor
D018076:DNA, Complementary; D005136:Eye Proteins; D009414:Nerve Growth Factors; D011506:Proteins; D015843:Serpins; D000099174:Pigment Epithelium-Derived Factor