Cloning and characterization of GRIPE, a novel interacting partner of the transcription factor E12 in developing mouse forebrain.
The helix-loop-helix (HLH) family of transcription factors are key contributors to a wide array of developmental processes, including neurogenesis and hematopoiesis. These factors are thought to exert their regulatory influences by binding to cognate promoter-DNA sequences as dimers. Although studies in mice have convincingly demonstrated that neurogenic HLH proteins such as NeuroD are intimately involved in neuronal fate determination, the role of the ubiquitously expressed HLH protein, E12, in mammalian neurogenesis remains ambiguous. To address this, a yeast two-hybrid interaction screen was employed to identify dimerization partners to E12. Screening of an embryonic day 11.5 forebrain library resulted in the cloning of GRIPE, a novel GAP-related interacting protein to E12. GRIPE binds to the HLH region of E12 and may require E12 for nuclear import. Furthermore, GRIPE may negatively regulate E12-dependent target gene transcription. High levels of GRIPE and E12 mRNA were coincidentally detected during embryogenesis, but only GRIPE mRNA levels remained high in adult brain, particularly in neurons of the cortex and hippocampus. These observations were recapitulated through an in vitro model of neurogenesis. Taken together, these results indicate that GRIPE is a novel protein dimerization of which with E12 has important consequences for cells undergoing neuronal differentiation.
Brain Development Group, Howard Florey Institute, University of Melbourne, Parkville, Melbourne, Victoria 3010, Australia.
Julian Ik Tsen
JI
Heng
Seong-Seng
SS
Tan
D000375:Aging; D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D002460:Cell Line; D002522:Chlorocebus aethiops; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D018257:Helix-Loop-Helix Motifs; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D016548:Prosencephalon / Q000254:growth & development / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D051820:TCF Transcription Factors; D058125:Transcription Factor 7-Like 1 Protein; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism*; D014162:Transfection
D004268:DNA-Binding Proteins; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D051820:TCF Transcription Factors; C544912:TCF7L1 protein, human; C544913:Tcf7l1 protein, mouse; D058125:Transcription Factor 7-Like 1 Protein; D014157:Transcription Factors; D004247:DNA