Regulation of CAD gene expression in mouse fibroblasts during the transition from the resting to the growing state.
We have analyzed the steady-state levels of CAD mRNA and ATCase activity in BALB/c 3T3 mouse fibroblasts at quiescence and at various time points following the initiation of serum stimulation. Steady-state levels of CAD mRNA in 3T3 cells following 12 h of serum stimulation increased 10-fold over levels measured at quiescence. In contrast to the observed increase in steady-state levels of CAD mRNA, its rate of transcription increased only 3-fold, suggesting that the expression of CAD gene in these cells is regulated at both the transcriptional and post-transcriptional levels, to a major extent by the latter. These increases in CAD mRNA in serum-stimulated cells were followed by parallel increases in ATCase activity as well. When comparing DNA synthesis [( 3H]thymidine uptake) to the accumulation of CAD mRNA and ATCase activity, it was observed that this accumulation occurred during the mid- to late-G1 phase of the cell cycle. These results suggest that the expression of CAD gene is cell growth dependent and may be a prerequisite to DNA synthesis.
D000581:Amidohydrolases / Q000235:genetics*; D000818:Animals; D001221:Aspartate Carbamoyltransferase / Q000235:genetics* / Q000378:metabolism; D015152:Blotting, Northern; D002223:Carbamoyl-Phosphate Synthase (Glutamine-Hydrolyzing) / Q000235:genetics* / Q000378:metabolism; D002453:Cell Cycle; D002460:Cell Line; D004080:Dihydroorotase / Q000235:genetics* / Q000378:metabolism; D005347:Fibroblasts; D005786:Gene Expression Regulation; D007399:Interphase; D051379:Mice; D008807:Mice, Inbred BALB C; D009097:Multienzyme Complexes / Q000235:genetics* / Q000378:metabolism; D009693:Nucleic Acid Hybridization; D011743:Pyrimidines / Q000096:biosynthesis*; D012333:RNA, Messenger / Q000032:analysis; D014158:Transcription, Genetic
C033626:CAD trifunctional enzyme; D009097:Multienzyme Complexes; D011743:Pyrimidines; D012333:RNA, Messenger; D001221:Aspartate Carbamoyltransferase; D000581:Amidohydrolases; D004080:Dihydroorotase; D002223:Carbamoyl-Phosphate Synthase (Glutamine-Hydrolyzing); C030986:pyrimidine