Characterization of gene structure and expression of two toll-like receptors from Japanese flounder, Paralichthys olivaceus.
We cloned the cDNAs and genes of two different types of toll-like receptors from Japanese flounder. The results of homology searches suggested that these genes (designated JF-TLR2 and JF-TLR22) are homologues of human TLR2 and fugu TLR22, respectively. The cDNAs of JF-TLR2 and JF-TLR22 encoded 818 and 961 amino acid residues, respectively. JF-TLR2 and JF-TLR22 contained two distinct structural/functional motifs of the TLR family, such as a leucine-rich repeat (LRR) domain in the extracellular portion and a toll/interleukin-1 receptor (TIR) domain in the intracellular portion. The genes of JF-TLR2 and JF-TLR22 consisted of 12 exons (4.9 kb in total length) and four exons (4.3 kb in total length), respectively. The first exon of each gene is a non-coding exon. Southern blot hybridization indicated that both JF-TLR2 and JF-TLR22 exist as single copies in the genome. These genes were mainly expressed in peripheral blood leukocytes (PBLs) and weakly expressed in PBL-rich organs such as kidney, spleen and gill. Expression of these genes was induced by both peptidoglycan and polyI:C, although the number of JF-TLR-expressing cells were not changed after induction. All of these results suggest that they are involved in the innate immune system.
Laboratory of Genome Science, Graduate School of Marine Science and Technology, Tokyo University of Marine Science and Technology, Konan 4-5-7, Minato-ku, 108-8477 Tokyo, Japan.
Ikuo
I
Hirono
Mariko
M
Takami
Masato
M
Miyata
Teruo
T
Miyazaki
Hyun-Ja
HJ
Han
Tomokazu
T
Takano
Makoto
M
Endo
Takashi
T
Aoki
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D005432:Flounder / Q000235:genetics* / Q000276:immunology*; D015870:Gene Expression; D007113:Immunity, Innate / Q000235:genetics; D007564:Japan; D008562:Membrane Glycoproteins / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000235:genetics*; D051195:Toll-Like Receptor 2; D051193:Toll-Like Receptors
D018076:DNA, Complementary; D008562:Membrane Glycoproteins; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D051195:Toll-Like Receptor 2; D051193:Toll-Like Receptors