Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.26.4 (RNase H)
 2,751 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Previous work from our laboratory demonstrated that CCAAT/enhancer-binding protein delta (C/EBP delta) functions in the initiation and maintenance of G(0) growth arrest in mouse mammary epithelial cells (MECs). In this report, we investigated the posttranscriptional and posttranslational regulation of C/EBP delta in G(0) growth-arrested mouse MECs. The results of transcriptional inhibitor studies demonstrated that the C/EBP delta mRNA exhibits a relatively short half-life in G(0) growth-arrested mouse MECs (t(1/2) approximately 35 min). In contrast, C/EBP delta mRNA has a longer half-life in G(0) growth-arrested mouse fibroblast cells (t(1/2) >100 min). Oligo/RNase H cleavage analysis and rapid amplification of cDNA ends-poly(A) test both confirmed the short C/EBP delta mRNA half-life observed in MECs and demonstrated that the C/EBP delta mRNA poly(A) tail is relatively short (approximately 100 nucleotides). In addition, the poly(A) tail length was not shortened during C/EBP delta mRNA degradation, which suggested a deadenylation-independent pathway. The C/EBP delta protein also exhibited a relatively short half-life in G(0) growth-arrested mouse MECs (t(1/2) approximately 120 min). The C/EBP delta protein was degraded in a ubiquitin-dependent manner, primarily in the nucleus, during G(0) growth arrest. In conclusion, these studies indicated that the C/EBP delta mRNA and protein content are under tight regulation in G(0) growth-arrested mouse MECs, despite the general concept that G(0) growth arrest is associated with a decrease in cellular activity.
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PMID:Posttranscriptional and posttranslational regulation of C/EBP delta in G0 growth-arrested mammary epithelial cells. 1255 32