title: Functional analysis of fish BCL-6 and Blimp-1 in vitro: transcriptional repressors for B-cell terminal differentiation in fugu (Takifugu rubripes).
abstract: The transcriptional repressors BCL-6 and Blimp-1 are key regulators of B-cell terminal differentiation in mammals. We have previously identified the BCL-6 gene and Blimp-1 gene in fugu (Takifugu rubripes). In the present report, we conducted a functional analysis of fugu BCL-6 and Blimp-1 by using a one-hybrid reporter assay with Gal4 fusion proteins and Gal4DBD luciferase reporter gene. Results from the reporter assays in mammalian cell lines (HeLa, HEK-293, CV-1 and NIH3T3) and the fish cell line EPC show that Gal4-BCL6 and Gal4-Blimp1 strongly repress the transcription of the luciferase gene in all cell lines. Furthermore, deletion analyses show that the N-terminal region of BCL-6 has transcriptional repression activity; the BTB/POZ domain is an especially potent repression domain. In contrast to BCL-6, although the N-acidic domain and PR domain are insufficient for repression, most functional motifs of Blimp-1 are associated with transcriptional repression. These results suggest that BCL-6 and Blimp-1 are functional transcriptional repressors in fugu and that they regulate B-cell terminal differentiation in fugu.
authors.affiliation: Laboratory of Marine Biotechnology, Faculty of Marine Bioscience, Fukui Prefectural University, 1-1 Gakuen-Chou, Obama, Fukui 917-0003, Japan.
authors.forename: Maki
authors.initials: M
authors.lastname: Ohtani
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Miyadai
mesh_terms: D020816:Amino Acid Motifs; D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology* / Q000378:metabolism; D002454:Cell Differentiation / Q000235:genetics*; D002460:Cell Line; D029941:Fish Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D041681:NIH 3T3 Cells; D017434:Protein Structure, Tertiary; D051560:Proto-Oncogene Proteins c-bcl-6 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D017384:Sequence Deletion; D023741:Takifugu / Q000235:genetics*; D014158:Transcription, Genetic
chemical_list: D029941:Fish Proteins; D051560:Proto-Oncogene Proteins c-bcl-6; D012333:RNA, Messenger; D012097:Repressor Proteins