Open AccessElements involved in anin vitroblock to transcription elongation at the end of the L1 mRNA family of adenovirus 2
Author(s) -
Orna Resnekov,
Ronald Pruzan,
Yosef Aloni
Publication year - 1991
Publication title -
nucleic acids research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 9.008
H-Index - 537
eISSN - 1362-4954
pISSN - 0305-1048
DOI - 10.1093/nar/19.8.1783
Subject(s) - biology , messenger rna , elongation , in vitro , transcription (linguistics) , genetics , microbiology and biotechnology , gene , linguistics , philosophy , materials science , metallurgy , ultimate tensile strength
Using the 3' end of the L1 mRNA family of adenovirus 2 (Ad2) as a model system, we investigated transcription elongation following a poly(A) signal in a cell-free system. The results show that RNA polymerase II can halt transcription elongation at a T-rich stretch in the non-coding DNA strand 20 nucleotides downstream of the poly(A) signal. The block to transcription elongation is enhanced when Sarkosyl is included in the elongation reaction. Deletion studies narrowed the region which directs the elongation block at the T-rich stretch, to an upstream fragment of 53 nucleotides that is very dA-rich and also contains a functional poly(A) signal. The deletion studies and analysis by site-directed mutagenesis indicate that in the present system, RNA secondary structure, the stretch of T's and the poly(A) signal are not the dominant elements responsible for the elongation block. The block to transcription elongation at the T-rich stretch was also shown to be 5 times more effective in an uninfected extract than in an Ad2 infected extract, which is reminiscent of the in vivo situation and is consistent with the suggestion that a trans-acting factor is involved in modulating the elongation block at the T-rich stretch.