Disease relevance of RPB2

• RPB2 encodes a protein of 138,750 daltons, which contains sequences implicated in binding purine nucleotides and zinc ions and exhibits striking sequence homology with the beta subunit of Escherichia coli RNA polymerase [1].
• The defects at the level of transcriptional elongation displayed by rtf1Delta, ctk1, fcp1 and rpb2 mutants also result in zymocin hypersensitivity [2].

High impact information on RPB2

• Although multiple functions have been assigned to the three largest subunits, RPB1, RPB2, and RPB3, the functions of the remaining smaller subunits are unknown [3].
• The RPB2 phylogeny shows with significant statistical support that taxa in Pezizomycotina with ascohymenial ontogeny (ascoma generally forms after nuclear pairing) are ancestral and paraphyletic, whereas ascolocular fungi with fissitunicate asci are a clade derived from them [4].
• Using high-resolution repair analysis, we determined the in vivo repair kinetics of cyclobutane pyrimidine dimers positioned around the transcription initiation site of RNAPII-transcribed genes RPB2 and URA3 [5].
• We found that repair of cyclobutane pyrimidine dimers in the transcribed strand of the expressed RPB2 gene in the chromosome of a repair-proficient strain is much more rapid than that in the nontranscribed strand [6].
• This gene, RPB2, exists in a single copy in the haploid genome [1].

Chemical compound and disease context of RPB2

• Supported by analogous results obtained for E. coli RNA polymerase using derivative VIII (2), we hypothesized that the second domain labeled by this derivative in the B150 subunit was domain I. Mutagenesis of the unique lysine present in domain I demonstrated that Lys 1102 was the target of derivative VIII [7].

Biological context of RPB2

• The gene for this subunit is present in single copy and maps to chromosome XV, where two other yeast RNA polymerase II subunits, RPB2 and RPB8, reside [8].
• Transcription-coupled and global genome repair in the Saccharomyces cerevisiae RPB2 gene at nucleotide resolution [9].
• A plasmid shuffle method was used to screen thoroughly for mutations in RPB2 that suppress a temperature-sensitive mutation, rpb1-1, which is located in region H of RPB1 [10].
• We investigated whether suppressor genetics could provide evidence for interactions between specific segments of RPB1 and RPB2 in Saccharomyces cerevisiae [10].
• We have cloned and sequenced the cDNA encoding the open reading frame of the mRNA of the second largest subunit of RNA polymerase II, or RPB2, of tomato [11].

Associations of RPB2 with chemical compounds

• Glycerol gradient fractionation of extracts of cells pulse-labeled for various times revealed that a subcomplex of RPB2 and RPB3 appears soon after subunit synthesis and can be chased into fully assembled enzyme [12].
• Sequence analysis of the rpb2-100 suppressor defined a cysteine replacement of the phylogenetically invariant arginine residue at position 512 (R512C), located within homology block D of Rpb2 [13].
• The repair of UV-induced photoproducts (cyclobutane pyrimidine dimers) in a well-characterized minichromosome, genomic DNA, and a transcribed genomic gene (RPB2) of a rad23delta mutant of Saccharomyces care was examined [14].
• Predicted zinc-binding motifs have been noted in the NH2-terminal part of B220 and the COOH-terminal region of B150 subunits [15].

Other interactions of RPB2

• When the results obtained with the RPB2 gene can be generalized, the RAD7 and RAD16 proteins not only are essential for repair of silenced regions but also function in repair of nontranscribed strands of active genes in S. cerevisiae [16].
• The soh1, soh2 and soh4 mutants were isolated as suppressors of the temperature-dependent growth of the hyperrecombination mutant hpr1 of Saccharomyces cerevisiae [17].
• SOH2 is identical to RPB2, which encodes the second largest subunit of RNA polymerase II, and SOH4 is the same as SUA7, encoding the yeast transcription initiation factor TFIIB [17].
• In cross-linking reactions dependent on transcription, RPB1, RPB2, and RPB5 were cross-linked with N(3)RdUTP [18].
• Additionally, the rate of repair of the transcribed and nontranscribed strands of the yeast RPB2 gene in the rad28 mutant is identical to that observed in wild-type cells following exposure to UV light [19].

Analytical, diagnostic and therapeutic context of RPB2

• Immunoprecipitation from 32P-labeled cell extracts revealed that three of the subunits, RPB1, RPB2, and RPB6, are phosphorylated in vivo [20].
• A 5586bp sequence (accession no. ), which includes the RNA polymerase II gene (RPB2) encoding the second largest protein subunit (RPB2), was obtained from the wheat biotype Phaeosphaeria nodorum (PN-w) by PCR amplification [21].
• Site-directed mutagenesis in the predicted metal-binding domain of B150 demonstrated its role in zinc binding [15].

References