title: Retention of duplicated ITAM-containing transmembrane signaling subunits in the tetraploid amphibian species Xenopus laevis.
abstract: The ITAM-bearing transmembrane signaling subunits (TSS) are indispensable components of activating leukocyte receptor complexes. The TSS-encoding genes map to paralogous chromosomal regions, which are thought to arise from ancient genome tetraploidization(s). To assess a possible role of tetraploidization in the TSS evolution, we studied TSS and other functionally linked genes in the amphibian species Xenopus laevis whose genome was duplicated about 40 MYR ago. We found that X. laevis has retained a duplicated set of sixteen TSS genes, all except one being transcribed. Furthermore, duplicated TCRα loci and genes encoding TSS-coupling protein kinases have also been retained. No clear evidence for functional divergence of the TSS paralogs was obtained from gene expression and sequence analyses. We suggest that the main factor of maintenance of duplicated TSS genes in X. laevis was a protein dosage effect and that this effect might have facilitated the TSS set expansion in early vertebrates.
authors.affiliation: Institute of Molecular and Cellular Biology, Siberian Branch of the Russian Academy of Sciences, Lavrentiev Avenue 8/2, Novosibirsk 630090, Russia; Novosibirsk State University, Pirogov Street 2, Novosibirsk 630090, Russia. Electronic address: sguselnikov@mcb.nsc.ru.
authors.forename: S V
authors.initials: SV
authors.lastname: Guselnikov
authors.affiliation: University of Rochester, Medical Center, 601 Elmwood Avenue, MRBX, Rochester, NY 14642, USA. Electronic address: Leon_Grayfer@urmc.rochester.edu.
authors.forename: L
authors.initials: L
authors.lastname: Grayfer
authors.affiliation: University of Rochester, Medical Center, 601 Elmwood Avenue, MRBX, Rochester, NY 14642, USA. Electronic address: f_dejesus7@yahoo.com.
authors.forename: F
authors.initials: F
authors.lastname: De Jesús Andino
authors.affiliation: National Center for Biotechnology Information NLM, National Institutes of Health, 8600 Rockville Pike, Bldg. 38A, Bethesda, MD, USA. Electronic address: rogozin@ncbi.nlm.nih.gov.
authors.forename: I B
authors.initials: IB
authors.lastname: Rogozin
authors.affiliation: University of Rochester, Medical Center, 601 Elmwood Avenue, MRBX, Rochester, NY 14642, USA. Electronic address: Jacques_Robert@urmc.rochester.edu.
authors.forename: J
authors.initials: J
authors.lastname: Robert
authors.affiliation: Institute of Molecular and Cellular Biology, Siberian Branch of the Russian Academy of Sciences, Lavrentiev Avenue 8/2, Novosibirsk 630090, Russia; Novosibirsk State University, Pirogov Street 2, Novosibirsk 630090, Russia. Electronic address: taranin@mcb.nsc.ru.
authors.forename: A V
authors.initials: AV
authors.lastname: Taranin
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D019143:Evolution, Molecular; D057809:HEK293 Cells; D006801:Humans; D061625:Immunoreceptor Tyrosine-Based Activation Motif / Q000235:genetics*; D008969:Molecular Sequence Data; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000235:genetics* / Q000276:immunology; D017452:Receptors, IgG / Q000235:genetics* / Q000276:immunology; D016415:Sequence Alignment; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology*; D057891:Tetraploidy; D014982:Xenopus laevis
chemical_list: D016693:Receptors, Antigen, T-Cell, alpha-beta; D017452:Receptors, IgG
keywords: Activating receptor complexes; Genome mining; Immunogenetics; Protein dosage effect; TCR; Tetraploidization; Xenopus