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The GAGA factor of Drosophila interacts with SAP18, a Sin3‐associated polypeptide
Author(s) -
Espinás Maria Lluïsa,
Canudas Sílvia,
Fanti Laura,
Pimpinelli Sergio,
Casanova Jordi,
Azorín Fernando
Publication year - 2000
Publication title -
embo reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.584
H-Index - 184
eISSN - 1469-3178
pISSN - 1469-221X
DOI - 10.1093/embo-reports/kvd046
Subject(s) - homeotic gene , repressor , biology , mutation , psychological repression , microbiology and biotechnology , genetics , gene , transcription factor , gene expression
SAP18, a polypeptide associated with the Sin3–HDAC co‐repressor complex, was identified in a yeast two‐hybrid screen as capable of interacting with the Drosophila GAGA factor. The interaction was confirmed in vitro by glutathione S ‐transferase pull‐down assays using recombinant proteins and crude SL2 nuclear extracts. The first 245 residues of GAGA, including the POZ domain, are necessary and sufficient to bind dSAP18. In polytene chromosomes, dSAP18 and GAGA co‐localize at a few discrete sites and, in particular, at the bithorax complex where GAGA binds some silenced polycomb response elements. When the dSAP18 dose is reduced, flies heterozygous for the GAGA mutation Trl 67 show the homeotic transformation of segment A6 into A5, indicating that GAGA–dSAP18 interaction contributes to the functional regulation of the iab ‐ 6 element of the bithorax complex. These results suggest that, through recruitment of the Sin3–HDAC complex, GAGA might contribute to the regulation of homeotic gene expression.