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Immunogenetics

, Volume 51, Issue 2, pp 117–128 | Cite as

Molecular cloning and linkage analysis of complement C3 and C4 genes of the Japanese medaka fish

  • N. Kuroda
  • K. Naruse
  • A. Shima
  • M. Nonaka
  • M. Sasaki
  • M. Nonaka
ORIGINAL PAPER

Abstract

 The thioester-containing complement components, C3 and C4, are believed to have arisen by gene duplication from a common ancestor, and the mammalian C4 gene resides in the vicinity of the C2 and B genes within the major histocompatibility complex (MHC) class III region. To analyze the evolution of both the complement system and the MHC, we determined the complete primary structures of two C3 genes, termed Orla C3-1 and Orla C3-2, and one C4 gene, termed Orla C4, of a teleost, Japanese medaka fish (Oryzias latipes), by analyzing cDNA clones isolated from a liver library constructed using the inbred AA2 strain. The deduced basic structures of Orla C3-1, C3-2, and C4, such as the subunit chain structure, the thioester site, and the proteolytic activation site, are similar to their mammalian counterparts. However, the catalytic His residue which greatly increases the rate of thioester reaction, is replaced by Ala in Orla C3-2, implying functional differentiation between two C3 molecules. Mapping analysis revealed a close linkage between the C3-1 and C3-2 genes, indicating that they arose by a local duplication rather than by a genome-wide tetraploidization. The C4 gene belongs to a different linkage group, and no linkage was observed among the C3, C4, Bf/C2, MHC class I, and MHC class II loci. These results suggest that the MHC class III complement region was established in the tetrapod lineage, or lost in the teleost lineage.

Key words Complement C3 C4 Medaka fish Linkage analysis 

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Copyright information

© Springer-Verlag Berlin Heidelberg 2000

Authors and Affiliations

  • N. Kuroda
    • 1
  • K. Naruse
    • 2
  • A. Shima
    • 3
  • M. Nonaka
    • 2
  • M. Sasaki
    • 1
  • M. Nonaka
    • 2
  1. 1.Department of Biochemistry, Nagoya City University Medical School, Nagoya, JapanJP
  2. 2.Department of Biological Sciences, Graduate School of Science, University of Tokyo, Tokyo 113-0033, Japan e-mail: mnonaka@biol.s.u-tokyo.ac.jp Tel.: +81-3-58003397 Fax: +81-3-58003397JP
  3. 3.Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, Tokyo, JapanJP

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