The GAGA factor of Drosophila interacts with SAP18, a Sin3-associated polypeptide.
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 Trl67 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.
Departament de Biologia Molecular i Cellular, Institut de Biologia Molecular de Barcelona, CSIC, Jordi Girona Salgado, Spain.
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ML
Espinás
S
S
Canudas
L
L
Fanti
S
S
Pimpinelli
J
J
Casanova
F
F
Azorín
D000005:Abdomen / Q000196:embryology; D000595:Amino Acid Sequence; D000818:Animals; D000071183:Autophagy-Related Proteins; D001665:Binding Sites; D002352:Carrier Proteins; D002828:Choristoma / Q000235:genetics; D002875:Chromosomes / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004330:Drosophila / Q000196:embryology* / Q000235:genetics / Q000378:metabolism; D029721:Drosophila Proteins; D006655:Histone Deacetylases / Q000378:metabolism*; D018398:Homeodomain Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008297:Male; D056245:Mi-2 Nucleosome Remodeling and Deacetylase Complex; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D029701:Saccharomyces cerevisiae Proteins; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D056264:Sin3 Histone Deacetylase and Corepressor Complex; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
C498649:ATG16 protein, S cerevisiae; D000071183:Autophagy-Related Proteins; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D018398:Homeodomain Proteins; D019476:Insect Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; C063460:Trl protein, Drosophila; C407043:bicoid interacting protein 1, Drosophila; D006655:Histone Deacetylases; D056245:Mi-2 Nucleosome Remodeling and Deacetylase Complex; D056264:Sin3 Histone Deacetylase and Corepressor Complex