Genes of the constant regions of functional immunoglobulin heavy chain of Japanese flounder, Paralichthys olivaceus

Abstract

IgM and IgD genes of the Japanese flounder were cloned and characterized from a genomic bacterial artificial chromosome (BAC) library. The micro gene contained four constant region exons (Cmi1-Cmi4), and two transmembrane exons (miTM1 and miTM2), which conforms to the organizational pattern of all other vertebrate micro-chain genes examined so far. In the same BAC clone, the delta gene, which is homologous to the IgD gene in mammals and teleost fish, was found immediately (0.9 kb) downstream of the IgM gene. This gene encoded seven exons (Cdelta1-Cdelta7) and two deltaTM exons (deltaTM1 and deltaTM2) and had no duplication of Cdelta1-Cdelta2, as found in Atlantic cod, or Cdelta2-Cdelta3-Cdelta4, as found in Atlantic salmon and channel catfish. Phylogenetic and sequence analyses strongly suggest that teleost delta is more closely related to non-IgM isotypes than IgM isotypes. The heavy chain (IgH) locus of Japanese flounder, which encodes microm, micros and deltam, was found to be fully functional.

Characterization of polyclonal antibodies against Japanese flounder IgM derived from recombinant IgM constant region proteins

“…Here, we report the production of 2 mouse polyclonal antiJapanese flounder IgM antibodies (pAb-IgM1 and pAb-IgM2) derived from recombinant Japanese flounder IgM constant region protein [7]. We show the sensitivity and specificity of the pAb-IgMs in vivo and demonstrate cross-reactivity of pAb-IgM2 in other fish species attributed to the specific conserved features of CHm4 of the IgM constant region.…”

The up-regulation of large yellow croaker secretory IgM heavy chain at early phase of immune response

“…In teleost, the IgM heavy chain possesses a translocon domain organization similar to the mammalian and amphibian IgM, that is V H1-n -D 1-n -J H1-n -C H1 -C H2 -C H3 -C H4 for secretory form and two additional transmembrane exons (TM1 and TM2) for membrane bound form (Litman et al 1999). To date, IgM heavy-chain genes have been cloned from various fish species including catfish, I. punctatus (Ghaffari and Lobb 1989;Wilson et al 1990), ladyfish, E. saurus (Amemiya and Litman 1990), Atlantic cod, G. morhua L., (Bengtén et al 1994), Atlantic salmon, S. salar L. (Hordvik et al 1992(Hordvik et al , 1997, rainbow trout, O. mykiss (Lee et al 1993;Andersson and Matsunaga 1993;Hansen et al 1994), holostean fish (bowfin, Amia calva and gar, Lepisosteus osseus) (Wilson et al 1995), zebrafish, Danio rerio (Danilova et al 2000), Antarctic teleost, Trematomus bernacchii (Coscia et al 2000), mandarin fish, Siniperca chuatsi (Zhang et al 2003), Japanese flounder, Paralichthys olivaceus (Lee et al 2001;Srisapoome et al 2004), Pufferfish, Takifugu rubripes (Saha et al 2005) and grouper, Epinephelus coioides (Cheng et al 2006). These studies revealed that the IgM heavy chain of teleosts shows differences in gene number, sequence diversity, and genetic organization of the putative elements.…”

Serum immunoglobulin M in Atlantic halibut (Hippoglossus hippoglossus): Characterisation of the molecule and its immunoreactivity

“…However, a large chimeric Ig chain, which shows gene sequence similarity to human and murine IgD heavy chain, has recently been described in channel catfish (Ictalurus punctatus) [7,8], Atlantic salmon (Salmo salar L.) [9], Atlantic cod (Gadus morhua) [10] and Japanese flounder (Paralichthys olivaceus) [11].…”