Transcription initiated by RNA polymerase II and purified transcription factors from liver. Cooperative action of transcription factors tau and epsilon in initial complex formation.

J W Conaway,D Reines,R C Conaway

doi:10.1016/s0021-9258(19)39149-5

J W Conaway, D Reines + Show 1 more

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https://doi.org/10.1016/s0021-9258(19)39149-5

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Abstract

Synthesis of accurately initiated transcripts has been reconstituted with RNA polymerase II and a set of five transcription factors purified from rat liver. In addition to three previously identified factors alpha, beta gamma, and delta (Conaway, R. C., and Conaway, J. W. (1989) Proc. Natl. Acad. Sci. U. S. A. 86, 7356-7360), transcription in the reconstituted liver system requires two novel factors designated tau and epsilon. These five transcription factors comprise two functional classes: (i) promoter recognition factors (tau and epsilon), which interact with template DNA to facilitate formation of a stable initial complex that is subsequently recognized and bound by RNA polymerase II, and (ii) RNA chain initiation factors (alpha, beta gamma, and delta), which do not participate in formation of the initial complex, but which are essential for transcription initiation.

Highlights

Synthesis of accurately initiated transcripts has been reconstituted with RNA polymerase II and a set of five transcription factors purified from rat liver
A. 66,7356-7360), transcription in the reconstituted liver system requires two novel factors designated T and t. These five transcription factors comprise two functional classes: (i) promoter recognition factors (T and t), which interact with template DNA to facilitate formation of a stable initial complex that is subsequently recognized and bound by RNA polymerase II, and (ii) RNA chain initiation factors (a, j37, and 6), which do not participate in formation of the initial complex, but which are essential for transcription initiation
System-We have fractionated rat liver and identified a set of five transcription factors that are essential for synthesis of accurately initiated transcripts by RNA polymerase II

Summary

Present address

Program in Molecular and Cell Biology, Oklahoma Medical Research Foundation, 825 N.E. 13th St., Oklahoma. Samuels and Sharp [24] purified [AB] from calf thymus and found it to be a multisubunit protein composed of 19-kDa and 13-kDa polypeptides, with a native molecular mass of 25 to 35 kDa. Reinberg et al [15] reported that partially purified preparations of TFIIA from HeLa cells contain a transcription factor with a native molecular mass of approximately 82 kDa, significantly larger than either STF or [AB]. Reinberg et al [15] reported that partially purified preparations of TFIIA from HeLa cells contain a transcription factor with a native molecular mass of approximately 82 kDa, significantly larger than either STF or [AB] These results are not inconsistent with the possibility that these investigators are describing different transcription factors. The apparent sizes of the two liver factors, which have been designated t and 7, are remarkably similar to the sizes reported for the HeLa cell transcription factors in fractions TFIID and [DB], respectively

PROCEDURES

RESULTS

BOOx g r

Nuclear extract

Preincubation 2 pN4 pDN pN4 v v pDN

DISCUSSION