Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.7.48 (transcriptase)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Expression of the A-type lamins was studied in the lung adenocarcinoma cell line GLC-A1. A-type lamins, consisting of lamin A and C, are two products arising from the same gene by alternative splicing. Northern blotting showed in GLC-A1 a relatively low expression level of lamin C and an even lower expression level of lamin A as compared to other adenocarcinoma cell lines. Immunofluorescence studies revealed highly irregular nuclear inclusions of lamin A, suggesting protein or gene expression abnormalities. Reverse transcriptase-polymerase chain reaction-based cDNA analysis followed by sequencing indicated the presence of an as yet unidentified alternative splicing product of the lamin A/C gene. This product differs from lamin A by the absence of the 5' part of exon 10 (90 nucleotides). Therefore we propose to designate this product lamin Adelta10. Deletion of the 30 amino acids encoded by exon 10 was predicted to result in a shift in pI of the protein from 7.4 to approximately 8.6, which was confirmed by two-dimensional immunoblotting. mRNA analysis in a variety of cell lines, normal colon tissue as well as carcinomas demonstrated the presence of lamin Adelta 10 in all samples examined, suggesting its presence in a variety of cell types.
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PMID:An alternative splicing product of the lamin A/C gene lacks exon 10. 862 84

The basic helix-loop-helix (bHLH) transcription factor, Hand1, plays an important role in the development of the murine extra-embryonic trophoblast cell lineage. In the present study, we have analysed the expression of Hand1 in human extra-embryonic cell types and determined its binding specificity and transcriptional activity upon interaction with different class A bHLH factors. Northern blotting and in situ hybridization showed that Hand1 mRNA is specifically expressed in amnion cells at different stages of gestation. Accordingly, we demonstrate that the protein is exclusively produced in the amniotic epithelium in vivo and in purified amnion cells in vitro using a novel polyclonal Hand1 antiserum. Reverse transcriptase-PCR and immunohistochemical staining of blastocysts revealed the production of Hand1 mRNA and polypeptide in the trophectodermal cell layer. In the presence of E12/E47, Hand1 stimulated the transcription of luciferase reporters harbouring degenerate E-boxes, suggesting that E-proteins are potential dimerization partners in trophoblastic tumour and amnion cells. In contrast, Hand1 diminished E12/E47-dependent transcription of reporters containing perfect E-boxes by inhibiting the interaction of Hand1/E-protein heterodimers with the palindromic cognate sequence. Furthermore, we show that Hand1 down-regulated GAL-E12-dependent reporter expression, indicating that the protein can also act directly as a transcriptional repressor. Mutational analyses of GAL-Hand1 suggested that two protein regions located within its N-terminal portion mainly confer the repressing activity. In conclusion, human Hand1 may play an important role in the differentiation of the amniotic membrane and the pre-implanting trophoblast. Furthermore, the data suggest that Hand1 can act as a repressor by two independent mechanisms; sequestration of class A bHLH factors from E-boxes and inhibition of their transcriptional activity.
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PMID:Human Hand1 basic helix-loop-helix (bHLH) protein: extra-embryonic expression pattern, interaction partners and identification of its transcriptional repressor domains. 1180 95

Hepatitis C virus (HCV) nonstructural protein 5B (NS5B) has RNA-dependent RNA polymerase (RdRp) activity. Because NS5B recognizes various RNA motifs besides the HCV genome, NS5B has the potential of interacting with host RNA molecules. In this study, an RNA pool enriched with the 3'-UTR sequences was generated and mRNA molecules with high affinity binding to NS5B were selected by iterative selection. Among the high binding mRNA 3'-UTR segments, we analyzed the housekeeping ribosomal protein S4, X-linked [RPS4X] mRNA 3'-UTR and the 3'-UTR of galectin-1 (GAL-1) mRNA, which is known to be one of the genes upregulated in HCV-infected liver cells and to have a wide spectrum of biological properties. By means of IP-RT-PCR, it was demonstrated that both of the mRNA molecules bind to NS5B in the cytoplasm. Interestingly, GAL-1 and RPS4X mRNA can serve as templates for NS5B RdRp, suggesting these RNA molecules are regulated in vivo by NS5B.
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PMID:In vitro selection of the 3'-untranslated regions of the human liver mRNA that bind to the HCV nonstructural protein 5B. 2450 63