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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
24
pubmed:dateCreated
2004-12-3
pubmed:abstractText
Mutations in the HNF1beta gene, encoding the dimeric POU-homeodomain transcription factor HNF1beta (TCF2 or vHNF1), cause various phenotypes including maturity onset diabetes of the young 5 (MODY5), and abnormalities in kidney, pancreas and genital tract development. To gain insight into the molecular mechanisms underlying these phenotypes and into the structure of HNF1beta, we functionally characterized eight disease-causing mutations predicted to produce protein truncations, amino acids substitutions or frameshift deletions in different domains of the protein. Truncated mutations, retaining the dimerization domain, displayed defective nuclear localization and weak dominant-negative activity when co-expressed with the wild-type protein. A frameshift mutation located within the C-terminal QSP-rich domain partially reduced transcriptional activity, whereas selective deletion of this domain abolished transactivation. All five missense mutations, which concern POU-specific and homeodomain residues, were correctly expressed and localized to the nucleus. Although having different effects on DNA-binding capacity, which ranged from complete loss to a mild reduction, these mutations exhibited a severe reduction in their transactivation capacity. The transcriptional impairment of those mutants, whose DNA-binding activity was weakly or not affected, correlated with the loss of association with one of the histone-acetyltransferases CBP or PCAF. In contrast to wild-type HNF1beta, whose transactivation potential depends on the synergistic action of CBP and PCAF, the activity of these mutants was not increased by the synergistic action of these two coactivators or by treatment with the specific histone-deacetylase inhibitor TSA. Our findings suggest that the complex syndrome associated with HNF1beta-MODY5 mutations arise from either defective DNA-binding or transactivation function through impaired coactivator recruitment.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0964-6906
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
13
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3139-49
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
HNF1beta/TCF2 mutations impair transactivation potential through altered co-regulator recruitment.
pubmed:affiliation
Biologie du Développement, UMR 7622, CNRS, Université Pierre et Marie Curie, 9 quai St Bernard, 75005 Paris, France.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't