Molecular and Cellular Biology, September 1999, p. 5847-5860, Vol. 19, No. 9
0270-7306/99/$04.00+0
Laboratory of Molecular Embryology, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892-5431
Received 23 March 1999/Returned for modification 17 May 1999/Accepted 2 June 1999
We investigated the protein associations and enzymatic requirements
for the Xenopus histone deacetylase catalytic subunit RPD3
to direct transcriptional repression in Xenopus oocytes. Endogenous Xenopus RPD3 is present in nuclear and
cytoplasmic pools, whereas RbAp48 and SIN3 are predominantly nuclear.
We cloned Xenopus RbAp48 and SIN3 and show that expression
of RPD3, but not RbAp48 or SIN3, leads to an increase in nuclear and
cytoplasmic histone deacetylase activity and transcriptional repression
of the TR
A promoter. This repression requires deacetylase activity and nuclear import of RPD3 mediated by a carboxy-terminal nuclear localization signal. Exogenous RPD3 is not incorporated into previously described oocyte deacetylase and ATPase complexes but cofractionates with a component of the endogenous RbAp48 in the oocyte nucleus. We
show that RPD3 associates with RbAp48 through N- and C-terminal contacts and that RbAp48 also interacts with SIN3. Xenopus
RbAp48 selectively binds to the segment of the N-terminal tail
immediately proximal to the histone fold domain of histone H4 in
vivo. Exogenous RPD3 may be targeted to histones through interaction
with endogenous RbAp48 to direct transcriptional repression of the
Xenopus TR
A promoter in the oocyte nucleus. However, the
exogenous RPD3 deacetylase functions to repress transcription in the
absence of a requirement for association with SIN3 or other targeted corepressors.
This article has been cited by other articles:
| J. Bacteriol. | J. Virol. | Eukaryot. Cell |
|---|
| Microbiol. Mol. Biol. Rev. | Clin. Vaccine Immunol. | All ASM Journals |
|---|