Chip interacts with diverse homeodomain proteins and potentiates bicoid activity in vivo.
The Drosophila protein Chip potentiates activation by several enhancers and is required for embryonic segmentation. Chip and its mammalian homologs interact with and promote dimerization of nuclear LIM proteins. No known Drosophila LIM proteins, however, are required for segmentation, nor for expression of most genes known to be regulated by Chip. Here we show that Chip also interacts with diverse homeodomain proteins using residues distinct from those that interact with LIM proteins, and that Chip potentiates activity of one of these homeodomain proteins in Drosophila embryos and in yeast. These and other observations help explain the roles of Chip in segmentation and suggest a model to explain how Chip potentiates activation by diverse enhancers.
Torigoi
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E
Molecular Biology Program, Sloan-Kettering Division of the Weill Graduate School of Medical Sciences of Cornell University, New York, NY 10021, USA.
Bennani-Baiti
I M
IM
Rosen
C
C
Gonzalez
K
K
Morcillo
P
P
Ptashne
M
M
Dorsett
D
D
D000818:Animals; D002846:Chromatography, Affinity; D004268:DNA-Binding Proteins / Q000378:metabolism; D004330:Drosophila / Q000196:embryology / Q000378:metabolism; D029721:Drosophila Proteins; D004742:Enhancer Elements, Genetic; D018398:Homeodomain Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008954:Models, Biological; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012097:Repressor Proteins; D015534:Trans-Activators / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D015533:Transcriptional Activation
C108740:Chi protein, Drosophila; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D018398:Homeodomain Proteins; D019476:Insect Proteins; D009687:Nuclear Proteins; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D015534:Trans-Activators; C056478:bcd protein, Drosophila; C083738:su(Hw) protein, Drosophila