| Literature DB >> 9261116 |
E K Crawford1, J E Ensor, I Kalvakolanu, J D Hasday.
Abstract
In unstimulated RAW 264.7 macrophage-like cells, tumor necrosis factor-alpha (TNF-alpha) mRNA was transcribed and accumulated in the cytoplasm, but the TNF-alpha transcripts failed to associate with polysomes, and TNF-alpha protein was not detected. Stimulation with lipopolysaccharide (LPS) induced an increase in TNF-alpha transcription, cytoplasmic TNF-alpha mRNA accumulation, polysome association, and secretion of TNF-alpha protein. This process was associated with a 200-nucleotide increase in the apparent length of the TNF-alpha mRNA. The difference in TNF-alpha mRNA size was caused by marked truncation of the 3' poly(A) tail in unstimulated cells. Fully adenylated TNF-alpha mRNA appeared within 15 min of LPS stimulation. We speculate that removal of the poly(A) tail blocks initiation of TNF-alpha translation in unstimulated macrophages. LPS inactivates this process, allowing synthesis of translatable polyadenylated TNF-alpha mRNA.Entities:
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Year: 1997 PMID： 9261116 DOI： 10.1074/jbc.272.34.21120
Source DB: PubMed Journal: J Biol Chem ISSN： 0021-9258 Impact factor: 5.157