Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.49 (reverse transcriptase)
 31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have established a spontaneously immortalized chicken embryo fibroblast (CEF) cell line (SC-1) that has been in continuous culture for more than three years. This is only the second report of a spontaneously immortalized reverse transcriptase (RT)-negative chicken cell line. The SC-1 cells emerged from crisis (at about passage 29-31) with a slower growth rate than primary cells. Passage 50 SC-1 cells expressed similar levels of p53 mRNA, but slightly lower levels of p53 protein than passage 6 CEF cells. By passage 120, p53 mRNA levels were significantly decreased in the SC-1 cells, while protein levels were slightly increased compared to passage 6 CEF cells. However, functional analysis of p53 revealed reduced activity in later passage SC-1 cells. Other p53-related genes including p21WAF1, p27Kip1, MDM-2, and the p16INK4a alternate reading frame (ARF) sequence showed similar patterns of differential mRNA expression. Levels of p15INK4b mRNA and protein were dramatically decreased in SC-1 cells, suggesting that the Rb pathway also has been compromised. Telomerase expression was undetectable in SC-1 cells. Fluorescence-activated cell sorting analysis showed that SC-1 and primary cells contained a similar proportion of G0/G1 phase cells, unlike the only other spontaneously immortalized chicken cell line (DF-1). The present study suggests that alterations in the p53 and Rb pathways cause fluctuations in expression levels of important cell-cycle regulatory genes during crucial transition periods as the SC-1 spontaneously immortalized chicken fibroblast cells progress toward becoming a fully committed cell line.
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PMID:Modulation of p53 expression and its role in the conversion to a fully immortalized chicken embryo fibroblast line. 1631 5

Mycobacterium avium subspecies paratuberculosis (MAP) and Mycobacterium avium subspecies avium (MAA) represent two closely related intracellular bacteria with vastly different associated pathologies. MAA can cause severe respiratory infections in immune compromised humans but is nonpathogenic in ruminants and is more readily controlled by the bovine immune system than MAP. MAP causes a fatal wasting syndrome in ruminants, typified by granulomatous enteritis localized in the small intestine. MAP has also been cited as a potential cause of human Crohn's disease. We used a bovine immune-specific microarray (BOTL-5) to compare the response of mature bovine monocyte-derived macrophages (MDM cells) to MAP and MAA. Statistical analysis of microarray data revealed 21 genes not appreciably expressed in resting MDM cells that were activated following infection with either MAA or MAP. Further analysis revealed 144 genes differentially expressed in MDM cells following infection with MAA and 99 genes differentially expressed following infection with MAP. Of these genes, 37 were affected by both types of mycobacteria, with three being affected in opposite directions. Over 41% of the differentially expressed genes in MAA and MAP infected MDM cells were members of, regulated by, or regulators of the MAPK pathways. Expression of selected genes was validated by quantitative real-time reverse transcriptase PCR and in several key genes (i.e., IL-2 receptor, tissue inhibitor of matrix metalloproteinases-1, and Fas-ligand) MAA was found to be a stronger activating factor than MAP. These gene expression patterns were correlated with prolonged activation of p38 MAPK and ERK1/2 by MAA, relative to MAP.
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PMID:Gene expression profiling of monocyte-derived macrophages following infection with Mycobacterium avium subspecies avium and Mycobacterium avium subspecies paratuberculosis. 1706 51