INVESTIGADORES
CERUTI Julieta Maria
congresos y reuniones científicas
Título:
NON PHOSPHORYLATED CREB REPRESSES GENE TRANSCRIPTION BY RECRUITING HDAC1.
Autor/es:
SIRKIN, PABLO; CERUTI, JULIETA; SCASSA, MAR¨ªA; C¨¢NEPA, EDUARDO
Lugar:
Iguaz¨², Argentina
Reunión:
Simposio; SAIB Protein Phosphorylation and Bioregulation Symposium (25 years); 2004
Institución organizadora:
SAIB
Resumen:
ST-C18.
NON PHOSPHORYLATED CREB REPRESSES GENE
TRANSCRIPTION BY RECRUITING HDAC1
Sirkin P, Ceruti J, Scassa M, C¨¢nepa E.
Lab. Biolog¨ªa Molecular, Depto Qu¨ªmica Biol¨®gica, FCEN, UBA,
Buenos Aires, Argentina. E-mail: ecanepa@qb.fcen.uba.ar
Transcription factor CREB, phosphorylated in S133, induce the
activity of a great variety of CRE-containing gene promoters. On
the contrary, unphosphorylated CREB cause an inhibitory effect
on transcription in several genes like 5-aminolevulinate synthase
(ALAS). The molecular basis of this inhibitory effect remains
unclear. Transfection experiments in HepG2 cells show that CREB
overexpression inhibits basal activity of ALAS/CAT fusion gene
and that this effect is blocked by cotransfection with CBP. As we
show using a ¦¤HAT-CBP mutant, HAT activity is crucial for CBP
action. Overexpression of HDAC1 counteracts the CBP rescue
effect. Similar results were observed on endogenous ALAS mRNA
in HepG2 cells as assessed by Northern blot.
Coimmunoprecipitation reveals a CREB-HDAC interaction in
HepG2 cells that is strongly impaired after cAMP stimulation.
We utilize a chromatin reconstitution approach on ALAS promoter
using Drosophila extracts and recombinant proteins to further
explore the CREB effects. Promoter activity were analysed by in
vitro transcription and primer extension. We show that P-CREB
and CBP increase ALAS expression. Excess of recombinant CREB
diminishes the transcriptional activity and HDAC co-addition
enhanced this inhibitory effect. We propose that CREB affects
gene expression in a phosphorylation status-dependent manner.
Non phosphorylated CREB recruits HDAC in order to maintain a
repressive condition. Phosphorylation at S133 disrupts HDAC
association and allows CBP engagement to render a productive
transcriptional initiation complex.¦¤HAT-CBP mutant, HAT activity is crucial for CBP
action. Overexpression of HDAC1 counteracts the CBP rescue
effect. Similar results were observed on endogenous ALAS mRNA
in HepG2 cells as assessed by Northern blot.
Coimmunoprecipitation reveals a CREB-HDAC interaction in
HepG2 cells that is strongly impaired after cAMP stimulation.
We utilize a chromatin reconstitution approach on ALAS promoter
using Drosophila extracts and recombinant proteins to further
explore the CREB effects. Promoter activity were analysed by in
vitro transcription and primer extension. We show that P-CREB
and CBP increase ALAS expression. Excess of recombinant CREB
diminishes the transcriptional activity and HDAC co-addition
enhanced this inhibitory effect. We propose that CREB affects
gene expression in a phosphorylation status-dependent manner.
Non phosphorylated CREB recruits HDAC in order to maintain a
repressive condition. Phosphorylation at S133 disrupts HDAC
association and allows CBP engagement to render a productive
transcriptional initiation complex.Drosophila extracts and recombinant proteins to further
explore the CREB effects. Promoter activity were analysed by in
vitro transcription and primer extension. We show that P-CREB
and CBP increase ALAS expression. Excess of recombinant CREB
diminishes the transcriptional activity and HDAC co-addition
enhanced this inhibitory effect. We propose that CREB affects
gene expression in a phosphorylation status-dependent manner.
Non phosphorylated CREB recruits HDAC in order to maintain a
repressive condition. Phosphorylation at S133 disrupts HDAC
association and allows CBP engagement to render a productive
transcriptional initiation complex.in
vitro transcription and primer extension. We show that P-CREB
and CBP increase ALAS expression. Excess of recombinant CREB
diminishes the transcriptional activity and HDAC co-addition
enhanced this inhibitory effect. We propose that CREB affects
gene expression in a phosphorylation status-dependent manner.
Non phosphorylated CREB recruits HDAC in order to maintain a
repressive condition. Phosphorylation at S133 disrupts HDAC
association and allows CBP engagement to render a productive
transcriptional initiation complex.transcription and primer extension. We show that P-CREB
and CBP increase ALAS expression. Excess of recombinant CREB
diminishes the transcriptional activity and HDAC co-addition
enhanced this inhibitory effect. We propose that CREB affects
gene expression in a phosphorylation status-dependent manner.
Non phosphorylated CREB recruits HDAC in order to maintain a
repressive condition. Phosphorylation at S133 disrupts HDAC
association and allows CBP engagement to render a productive
transcriptional initiation complex.s the transcriptional activity and HDAC co-addition
enhanced this inhibitory effect. We propose that CREB affects
gene expression in a phosphorylation status-dependent manner.
Non phosphorylated CREB recruits HDAC in order to maintain a
repressive condition. Phosphorylation at S133 disrupts HDAC
association and allows CBP engagement to render a productive
transcriptional initiation complex.s-dependent manner.
Non phosphorylated CREB recruits HDAC in order to maintain a
repressive condition. Phosphorylation at S133 disrupts HDAC
association and allows CBP engagement to render a productive
transcriptional initiation complex.