The homeodomain of Tinman mediates homo- and heterodimerization of NK proteins.
Cardiac development requires the action of transcription factors, which control the specification and differentiation of cardiac cell types. One of these factors, encoded by the homeobox gene tinman (tin), is essential for the specification of all cardiac cells in Drosophila. An increasing number of examples show that protein-protein interactions can be important for determining the specific transcriptional activities of homeodomain proteins, in addition to their binding to specific DNA target sites. Here, we show that Tin and Bagpipe (Bap), another homeodomain protein, form homo- and heterodimeric complexes. We demonstrate that homo- and heterodimerization of Tin is mediated through its homeodomain and that the region required for this interaction corresponds to the first two helices that are also necessary for DNA binding. We further show that, in the yeast system, the homeodomain can function as a transcriptional repressor domain. These findings suggest that protein-protein interactions of Tin play a role in its transcriptional and developmental functions.
Zaffran
Stéphane
S
Brookdale Department of Molecular, Cell and Developmental Biology, Box 1020, Mount Sinai School of Medicine, New York, NY 10029, USA. zeffrans@pasteur.fr
Frasch
Manfred
M
D001665:Binding Sites; D019281:Dimerization; D029721:Drosophila Proteins / Q000737:chemistry* / Q000378:metabolism*; D018398:Homeodomain Proteins / Q000737:chemistry* / Q000378:metabolism*; D011485:Protein Binding; D025941:Protein Interaction Mapping; D017434:Protein Structure, Tertiary; D012097:Repressor Proteins / Q000737:chemistry* / Q000378:metabolism*; D013329:Structure-Activity Relationship; D015534:Trans-Activators / Q000737:chemistry* / Q000378:metabolism*; D014157:Transcription Factors / Q000737:chemistry* / Q000378:metabolism*
D029721:Drosophila Proteins; D018398:Homeodomain Proteins; D012097:Repressor Proteins; D015534:Trans-Activators; D014157:Transcription Factors; C104163:bagpipe protein, Drosophila; C102933:tin protein, Drosophila; C094797:vnd protein, Drosophila