Open AccessThe C-terminal repeat domain of RNA polymerase II largest subunit is essential in vivo but is not required for accurate transcription initiation in vitro.
Author(s) -
William A. Zehring,
J M Lee,
J R Weeks,
R. S. Jokerst,
Arno L. Greenleaf
Publication year - 1988
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.85.11.3698
Subject(s) - biology , microbiology and biotechnology , rna polymerase ii , transcription (linguistics) , rna polymerase , polymerase , protein subunit , exon , rna , biochemistry , gene , promoter , gene expression , linguistics , philosophy
DNA sequence analysis of RpII215, the gene that encodes the Mr215,000 subunit of RNA polymerase II (EC 2.7.7.6) in Drosophila melanogaster, reveals that the 3'-terminal exon includes a region encoding a C-terminal domain composed of 42 repeats of a seven-residue amino acid consensus sequence, Tyr-Ser-Pro-Thr-Ser-Pro-Ser. A hemi- and homozygous lethal P-element insertion into the coding sequence of this domain causes premature translation termination and therefore truncation of the protein, leaving only 20 heptamer repeats. While loss of approximately 50% of the repeat structure in this mutant is a lethal event in vivo, enzyme containing the truncated subunit remains capable of accurate initiation at promoters in vitro. Moreover, treatment of purified intact RNA polymerase II with protease, to remove the entire repeat domain, does not eliminate the enzyme's ability to initiate accurately in vitro. Possible in vivo functions for this unusual protein domain are considered in light of these results.