Architectural factor HMGA induces promoter bending and recruits C/EBP and GATA during silkmoth chorion gene regulation.
A protein displaying significant similarity to mammalian HMGA (high-mobility group A) proteins, but also bearing unique structural features, was isolated from silkmoth (Bombyx mori) follicular cells. This factor, named BmHMGA, exhibits specific binding preference for chorion gene promoter elements and induces DNA bending thereon. BmHMGA deploys temporal-specific interaction with transcription factors BmC/EBP (C/EBP is CCAAT/enhancer-binding protein) and BmGATAbeta during follicle maturation. The respective protein complexes can be detected on chorion gene promoters in vivo, with different developmental profiles each time. Analogous interaction takes place on the putative promoter of the BmC/EBP gene, hinting towards a transcriptional circuit that is responsible for the progress of choriogenesis as a whole. Finally, transient suppression of BmHMGA expression led to down-regulation of chorion genes and the BmC/EBP gene, and revealed recruitment of BmC/EBP, BmGATAbeta and TFIID (transcription factor IID)/TBP (TATA-box-binding protein) by BmHMGA. A revised model for chorion gene regulation is discussed in view of these findings.
Papantonis
Argyris
A
Department of Biochemistry and Molecular Biology, Faculty of Biology, National and Kapodistrian University of Athens, 15701 Athens, Greece.
Vanden Broeck
Josef
J
Lecanidou
Rena
R
D000818:Animals; D012831:Bombyx; D022762:CCAAT-Enhancer-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D002823:Chorion / Q000254:growth & development*; D005260:Female; D050980:GATA Transcription Factors / Q000378:metabolism*; D017353:Gene Deletion; D018507:Gene Expression Regulation, Developmental; D017344:Genes, Insect / Q000502:physiology*; D024003:HMGA Proteins / Q000378:metabolism / Q000494:pharmacology*; D008969:Molecular Sequence Data; D020411:Oligonucleotide Array Sequence Analysis; D011401:Promoter Regions, Genetic / Q000502:physiology*; D020798:Two-Hybrid System Techniques
D022762:CCAAT-Enhancer-Binding Proteins; D050980:GATA Transcription Factors; D024003:HMGA Proteins