Growth-dependent repression of human adenine nucleotide translocator-2 (ANT2) transcription: evidence for the participation of Smad and Sp family proteins in the NF1-dependent repressor complex
2008 (English)In: Biochemical Journal, ISSN 0264-6021, E-ISSN 1470-8728, Vol. 412, 123-130 p.Article in journal (Refereed) Published
NF1 (nuclear factor 1) binds to two upstream elements of the human ANT2 (adenine nucleotide translocator-2) promoter and actively represses expression of the gene in growth-arrested diploid skin fibroblasts [Luciakova, Barath, Poliakova, Persson and Nelson (2003) J. Biol. Chem. 278, 30624-30633]. ChIP (chromatin immunoprecipitation) and co-immunoprecipitation analyses of nuclear extracts from growth-arrested and growth-activated diploid cells demonstrate that NF1, when acting as a repressor, is part of a multimeric complex that also includes Smad and Sp-family proteins. This complex appears to be anchored to both the upstream NF1-repressor elements and the proximal promoter, Sp1-dependent activation elements in growth-arrested cells. In growth-activated cells, the repressor complex dissociates and NF1 leaves the promoter. As revealed by co-immunoprecipitation experiments, NF1-Smad4-Sp3 complexes are present in nuclear extracts only from growth-inhibited cells, suggesting that the growth-state-dependent formation of these complexes is not an ANT2 promoter-specific event. Consistent with the role of Smad proteins in the repression complex, TGF-beta (transforming growth factor-beta) can fully repress ANT2 transcription in normally growing fibroblasts. Finally, pull-down experiments of in vitro transcribed/translated NF1 isoforms by GST (glutathione transferase)-Smad and GST-Smad MH fusion proteins indicate direct physical interactions between members of the two families. These findings suggest a possible functional relationship between the NF1 and Smad proteins that has not been previously observed.
Place, publisher, year, edition, pages
2008. Vol. 412, 123-130 p.
adenine nucleotide translocator-2, human diploid fibroblast, nuclear factor-1 (NF1), protein interaction, repression, transforming growth factor-beta
Biochemistry and Molecular Biology
IdentifiersURN: urn:nbn:se:su:diva-58551DOI: 10.1042/BJ20071440ISI: 000256049800013OAI: oai:DiVA.org:su-58551DiVA: diva2:421011
authorCount :42011-06-072011-06-032011-06-07Bibliographically approved