Showing papers on "Transcription factor published in 1982"

Transcription of adenovirus 5 early region 1b is elevated in permissive cells infected by a mutant with an upstream deletion.

Abstract: Early region 1b (E1b) of adenovirus 5 consists of a single transcription unit that lies from 1,702 to 4,070 nucleotides from the conventional left end of the genome. The effect of mutations that map upstream of E1b on the production of E1b mRNA was examined in vivo with mutants defective in gene functions from the neighboring early region 1a (E1a) transcription unit (499 to 1,632 nucleotides from the left end). These host range mutants replicate in the adenovirus 5-transformed human cell line 293. E1b mRNA accumulation was assayed by DNA-RNA hybridization late after productive infection when the E1b transcripts are abundant in the cytoplasm. Cells infected by wild-type virus, mutant dl311, or mutant hr1. The elevated levels of E1b mRNA were also detected in steady-state nuclear RNA, pulse-labeled polyadenylated nuclear RNA, and pulse-labeled total nuclear RNA. These data indicate that E1b transcription was elevated in human 293 cells infected with dl312. There was no evidence of increases in genomic DNA in dl312-infected cells, suggesting that the rate of transcription may be elevated. When mixed infections with a 10-fold excess of either dl312 or wild-type virus were performed, the phenotype was that of the more abundant genome. This result suggests that the respective phenotypes were cis dominant. The increased rate of transcription can be attributed to cis-active regulatory effects of the deletion of nucleotides 448 to 1,349 in mutant dl312 DNA.

Peptide maps of regulatory subunits of Bacillus subtilis RNA polymerase.

Abstract: Peptide maps of four regulatory subunits of Bacillus subtilis RNA polymerase were obtained. Three sigma-like proteins (sigma 55, sigma 37, and sigma 29) as well as the transcription modification factor, delta (delta) protein, were shown to give unique peptide patterns. This observation demonstrates that each is a distinct protein species; none is derived from another by a simple proteolytic modification. Images

THE IN VITRO TRANSCRIPTION OF DROSOPHILA tRNA GENES

Abstract: Extracts derived from Drosophila Kc cells, Hela cells and Xenopus oocytes support accurate in vitro transcription of cloned Drosophila tRNA genes. By analyzing the transcription activity of native and mutant tRNA genes we have identified the sequences required for transcription initiation and termination. The primary transcripts have purine triphosphates at their 5′-ends and leader sequences of 3–15 bases. The exact initiation site is dependent on the nature of the 5′ flanking sequence. T 5 sequences are efficient termination signals. Less efficient termination occurs in T-rich stretches. Our results show that transcription of tRNA genes is controlled by two regions within the mature tRNA coding sequence. In the tRNA these two regions code for the D-stem/D-loop (D-control region) and the T-stem/T-loop (T-control region). Promotion of tRNA gene transcription is mediated by tRNA gene specific transcription factors. These factors bind cooperatively to the D- and the T-control regions; shortening or lengthening the spacer distance between the two control regions, reduces the ability of factors to bind cooperatively. Although the binding of a putative factor to the D-control region can occur in the absence of the T-control region, factor binding appears to be sequential. Cooperativity is dependent upon factor binding to the T-control region. Once factor binds to the T-control region a transcription complex is formed which is stable for many rounds of transcription initiation.