Disease relevance of RPB7

• Previous reports of glucan-induced activity against a B16 murine melanoma were not confirmed [1].
• L5178Y murine lymphoblastic leukemia, B16 melanoma, BW10232 adenocarcinoma, and 15091A anaplastic carcinoma were implanted 7 to 11 days prior to enzyme injection in the appropriate host [2].
• The biological half-life of the enzyme was approximately 21 hours in several mammalian species (mice without and with BW10232 adenocarcinoma and B16 melanoma, rats, and monkeys) after a single injection; however, upon repeated administration, phenylalanine ammonia-lyase had a much shorter biological half-life [3].
• Their in vitro antitumor activities against murine B16 melanoma and P388 leukemia cells were determined [4].
• Glucan sulfate (250 mg/kg, i.v.) increased (P less than 0.05) median survival time of C57B1/6J mice with syngeneic melanoma B16 or sarcoma M5076 [5].

High impact information on RPB7

• We have determined the crystal structure of the complex between the Methanococcus jannaschii subunits E and F, the archaeal homologs of RPB7 and RPB4 [6].
• Loss of the Rpb4/Rpb7 subcomplex in a mutant form of the Rpb6 subunit shared by RNA polymerases I, II, and III [7].
• Consistent with the growth phenotype, overexpression of RPB7 could suppress the transcriptional defect characteristic of rpb4Delta cells during the mild, but not during a more severe, heat shock [8].
• We identified a partially sequenced Saccharomyces cerevisiae gene which encodes a protein related to the S. cerevisiae RNA polymerase II subunit, RPB7 [9].
• C25, like RPB7, is present in submolar ratios, easily dissociates from the enzyme, is essential for cell growth and viability, but is not required in certain transcription assays in vitro [9].

Chemical compound and disease context of RPB7

• In the syngeneic B16 melanoma tumor model tiprotimod significantly prolonged the medium survival time and reduced the number of visuable metastases in the lungs even when applied after resection of the primary tumor graft [10].
• Two bacterial strains B16 (Pseudomonas aeruginosa) and DT4 (Pseudomonas sp.) isolated by enrichment technique were found to utilize 2-chlorobenzoic acid (2-Cba) and 4-chlorobenzoic acid (4-Cba) respectively as sole source of carbon and energy [11].

Biological context of RPB7

• In S.cerevisiae, RPB7 is essential for cell viability while rpb4 null strains are temperature sensitive at low and high temperatures [12].
• We also show that high expression levels of S.cerevisiae RPB7 and its homologs rescue the sporulation defect of rpb4 homozygous null diploids, but only some of them cause significant enhancement of the pseudohyphal phenotype [12].
• We showed that in strain HCY53, the mini-Tn3 was inserted at the distal end of an essential gene RPB7, which encodes one of the two subunits, Rpb4-Rbp7, that forms a subcomplex with RNA polymerase II [13].
• The defective phenotype of strain HCY53 could be corrected by a plasmid bearing the entire RPB7 gene [13].
• We present a model whereby the stoichiometry of Rpb4 and Rpb7 and their relative levels in the cell play a switch like role in establishing either sporulation or pseudohyphal gene expression [14].

Anatomical context of RPB7

• Two murine (AKR, B16) and four human (HTB-31, KB, MOSER, RCA) cell lines were used to evaluate 2000 fermentation broth supernatants [15].
• Screening of cDNA libraries prepared from HeLa cells, Epstein-Barr virus transformed lymphocytes, and normal human brain showed that the NOV protein interacts with the rpb7 subunit of RNA polymerase in a yeast two hybrid system [16].

Associations of RPB7 with chemical compounds

• An allele of the yeast RPB7 gene, encoding an essential subunit of RNA polymerase II, reduces cellular resistance to the antitumor drug bleomycin [13].

Physical interactions of RPB7

• Use of the yeast two-hybrid analysis in conjunction with computational analysis of the recently reported crystal structure of Rpb4/Rpb7 sub-complex allowed us to identify regions previously not suspected to be involved in the functional interaction of these proteins [17].
• Saccharomyces cerevisiae Rpb7 also interacted with Nrd1, indicating that the interaction is conserved in evolution [18].

Other interactions of RPB7

• Whereas RPB7 is essential, RPB4 is dispensable for cellular viability [19].
• Under certain circumstances, RPB3, RPB4, and RPB7 were cross-linked [20].

References