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Mammalian Elongin A complex mediates DNA‐damage‐induced ubiquitylation and degradation of Rpb1
Author(s) -
Aso Teijiro,
Kamura Takumi,
Kitajima Shigetaka,
Conaway Ronald C,
Conaway Joan W,
Yasukawa Takashi
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.495.2
Subject(s) - rna polymerase ii , protein subunit , ubiquitin , microbiology and biotechnology , biology , transcription (linguistics) , dna damage , dna , biochemistry , gene expression , gene , linguistics , promoter , philosophy
The Elongin complex stimulates the rate of transcription elongation by RNA polymerase II (pol II) by suppressing transient pausing of the pol II at many sites along the DNA. Elongin is composed of a transcriptionally active A subunit and two small regulatory B and C subunits, which can form an isolable Elongin BC subcomplex. Here, we have shown that both the ubiquitylation and proteasomal degradation of the largest subunit of pol II (Rpb1) following UV‐irradiation are significantly suppressed in Elongin A‐deficient cells; however, in both cases suppression is rescued by transfection of wild‐type Elongin A. Moreover, we have demonstrated that the Elongin A‐Elongin BC complex is capable of assembling with the Cul5/Rbx2 module, and that this hetero‐pentamer complex efficiently ubiquitylates Rpb1 in vitro. Mechanistic studies indicate that colocalization of Elongin A and Cul5 in cells and the interaction of Elongin A with the Ser5‐phosphorylated form of Rpb1 are strongly enhanced following UV‐irradiation. Taken together, our results suggest that mammalian Elongin A is directly involved in ubiquitylation and degradation of Rpb1 following DNA damage.