Multiple mechanisms confining RNA polymerase II ubiquitylation to polymerases undergoing transcriptional arrest.
Cell
; 121(6): 913-23, 2005 Jun 17.
Article
en En
| MEDLINE
| ID: mdl-15960978
ABSTRACT
In order to study mechanisms and regulation of RNA polymerase II (RNAPII) ubiquitylation and degradation, highly purified factors were used to reconstitute RNAPII ubiquitylation in vitro. We show that arrested RNAPII elongation complexes are the preferred substrates for ubiquitylation. Accordingly, not only DNA-damage-dependent but also DNA-damage-independent transcriptional arrest results in RNAPII ubiquitylation in vivo. Def1, known to be required for damage-induced degradation of RNAPII, stimulates ubiquitylation of RNAPII only in an elongation complex. Ubiquitylation of RNAPII is dependent on its C-terminal repeat domain (CTD). Moreover, CTD phosphorylation at serine 5, a hallmark of the initiating polymerase, but not at serine 2, a hallmark of the elongating polymerase, completely inhibits ubiquitylation. In agreement with this, ubiquitylated RNAPII is hypophosphorylated at serine 5 in vivo, and mutation of the serine 5 phosphatase SSU72 inhibits RNAPII degradation. These results identify several mechanisms that confine ubiquitylation of RNAPII to the forms of the enzyme that arrest during elongation.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Transcripción Genética
/
ARN Polimerasa II
/
Ubiquitina
Tipo de estudio:
Prognostic_studies
Idioma:
En
Revista:
Cell
Año:
2005
Tipo del documento:
Article
País de afiliación:
Reino Unido