title: Cell type-dependent transactivation or repression of mesoderm-restricted basic helix-loop-helix protein, POD-1/Capsulin.
abstract: A family of basic-helix-loop-helix (bHLH) nuclear factors play important roles in controlling cell growth and differentiation as critical regulatory components in transcription. Here we describe molecular characterization of mesoderm-specific bHLH protein, POD-1/Capsulin. Transactivation property of POD-1/Capsulin was analyzed by the Gal4 fusion system in six mammalian cell lines. The results indicated that an activation property was shown in HT1080 and HeLa cells, but a repression activity in HepG2 cells. Mapping analysis for the transactivation and repression activities revealed that the C-terminal domain of POD-1/Capsulin is essential for the transactivation and both the N-terminal and C-terminal domains are contributed to the repression activities. Furthermore, in order to identify possible interactants of the POD-1/Capsulin, we performed yeast two-hybrid screen in a human kidney cDNA library, and identified a class A bHLH protein, ITF-2 as potential heterodimeric partner of the bHLH protein.
authors.affiliation: Center for Institute of Applied Biochemistry, Institute of Applied Biochemistry, University of Tsukuba, Ibaraki, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Miyagishi
authors.forename: M
authors.initials: M
authors.lastname: Hatta
authors.forename: T
authors.initials: T
authors.lastname: Ohshima
authors.forename: J
authors.initials: J
authors.lastname: Ishida
authors.forename: R
authors.initials: R
authors.lastname: Fujii
authors.forename: T
authors.initials: T
authors.lastname: Nakajima
authors.forename: A
authors.initials: A
authors.lastname: Fukamizu
mesh_terms: D016475:3T3 Cells; D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins; D015153:Blotting, Western; D019556:COS Cells; D002460:Cell Line; D005982:Glutathione Transferase / Q000378:metabolism; D006367:HeLa Cells; D018257:Helix-Loop-Helix Motifs; D006801:Humans; D008648:Mesoderm / Q000378:metabolism*; D051379:Mice; D011233:Precipitin Tests; D017434:Protein Structure, Tertiary; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014407:Tumor Cells, Cultured; D020798:Two-Hybrid System Techniques; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D005982:Glutathione Transferase; D014157:Transcription Factors; D001616:beta-Galactosidase; C491825:TCF21 protein, human; C112923:Tcf21 protein, mouse