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.
Hirono
Ikuo
I
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.
Takami
Mariko
M
Miyata
Masato
M
Miyazaki
Teruo
T
Han
Hyun-Ja
HJ
Takano
Tomokazu
T
Endo
Makoto
M
Aoki
Takashi
T
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