title: Regulation of antigen-receptor gene assembly in hagfish.
abstract: Variable lymphocyte receptors (VLRs) are antigen receptors in the jawless vertebrates lamprey and hagfish. VLR genes are classified into VLRA and VLRB, and lymphocytes expressing VLRA are T-cell-like, whereas those expressing VLRB are B-cell-like in the sea lamprey. Diverse VLR genes are assembled somatically in lymphocytes; however, how the assembly is regulated is still largely unknown. Here, we analyse VLR gene assembly at the single-cell level in the inshore hagfish (Eptatretus burgeri). Each lymphocyte assembles and transcribes only one type of VLR gene, either VLRA or VLRB. In general, monoallelic assembly of VLR was observed, but diallelic assembly was found in some cases--in many of which, one allele was functional and the other was defective. In fact, all VLR-assembled lymphocytes contained at least one functional VLR gene. Together, these results indicate a feedback inhibition of VLR assembly and selection of VLR-positive lymphocytes.
authors.affiliation: Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, 2-11-16, Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.
authors.forename: Natsuko
authors.initials: N
authors.lastname: Kishishita
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Matsuno
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Takahashi
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Takaba
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Nishizumi
authors.forename: Fumikiyo
authors.initials: F
authors.lastname: Nagawa
mesh_terms: D000483:Alleles; D000818:Animals; D005786:Gene Expression Regulation / Q000276:immunology; D015321:Gene Rearrangement / Q000235:genetics*; D006196:Hagfishes / Q000235:genetics* / Q000276:immunology; D007135:Immunoglobulin Variable Region / Q000235:genetics; D008954:Models, Biological; D011946:Receptors, Antigen / Q000235:genetics*; D014158:Transcription, Genetic / Q000502:physiology
chemical_list: D007135:Immunoglobulin Variable Region; D011946:Receptors, Antigen