Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.3.1.28 (chloramphenicol acetyltransferase)
 5,100 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Gene H1t encodes a testis-specific variant of the H1 histone family expressed in pachytene spermatocytes during the meiotic phase of spermatogenesis. Fusions between various upstream fragments of the H1t gene and the chloramphenicol acetyltransferase-encoding reporter gene were analyzed in mouse L cells by both transient and permanent transfection. Expression of the minimal promoter [174 nucleotides (nt) upstream from the transcription start point] was enhanced by sequences extending to nt -693, but was reduced in constructs with kb of upstream sequence. Using synchronized cells, expression was at least twofold higher in growing than in inhibited cells. Thus, the H1t promoter is modulated both positively and negatively by distant upstream sequences, and it displays some of the S-phase-dependent character of a replication-dependent histone.
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PMID:Analysis of the promoter for the gene encoding the testis-specific histone H1t in a somatic cell line: evidence for cell-cycle regulation and modulation by distant upstream sequences. 153 53

A 6.86 kb rat genomic DNA fragment containing the testis-specific histone H1t gene and the histone H4t gene has been sequenced. S1-nuclease protection analyses of total cellular RNA from rat liver and testis showed that histone H1t mRNA was present only in testis. Examination of various highly enriched populations of rat testis cell types revealed that H1t mRNA was found exclusively in a fraction enriched in pachytene spermatocytes. When protein, DNA interactions within the proximal promoter region of the histone H1t gene were examined by electrophoretic mobility shift assays, only minor differences were found in mobility shift patterns of the H1t promoter in assays comparing binding of nuclear proteins from pachytene spermatocytes and early spermatids. However, major differences in binding were observed upon comparing nuclear proteins from rat pachytene spermatocytes to liver. Comparison of binding patterns of rat testis, rat hepatoma H4 cells, HeLa cells, and COS-1 cells also revealed dramatic differences. Transcriptional activity of the histone H1t promoter was examined by measuring H1t promoted chloramphenicol acetyltransferase (CAT) mRNA levels in transient expression assays in transfected rat hepatoma H4 cells, HeLa cells, and COS-1 cells. These assays revealed that the histone H1t promoted CAT gene functioned poorly in HeLa cells and COS-1 cells compared to expression with the parent SV40 promoted vector pSV2CAT. The H1t promoted CAT gene apparently did not work at all in transfected rat hepatoma H4 cells, which is consistent with testis germinal cell specific expression of the histone H1t gene.
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PMID:Structural and functional analysis of the rat testis-specific histone H1t gene. 213 96

The testis-specific histone gene H1t is expressed only in mammalian testis at the stage of pachytene spermatocytes. The tissue-specific regulation of the mouse H1t gene was examined in mouse testicular primary culture cells with gene constructs consisting of H1t promoter elements fused to the chloramphenicol acetyltransferase or the firefly luciferase reporter gene. Our experiments demonstrate that expression of the mouse H1t gene is enhanced by a conserved H1 histone gene-specific TG box 452 base pairs upstream of the transcription start site. The transcription of the H1t gene appears to be reduced by sequences between -1999 and -1506. No regulatory effect could be shown for the H1 box in the expression of the mouse H1t gene. Binding of nuclear protein extracted from mouse testis to these consensus elements was shown by electrophoretic mobility-shift assays with mouse testicular nuclear proteins and labeled oligonucleotides containing the upstream TG box sequences or the two testis-specific elements of the H1t gene.
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PMID:Testis-specific expression of the mouse histone gene H1t is regulated by several promoter elements. 940 43