Cloning and sequence analysis of cDNA for the proteasome activator PA28-beta subunit of flounder (Paralichthys olivaceus).
Proteasome is a large multisubunit complex involved in intracellular proteolysis in antigen processing for loading MHC class I molecules. Two activators PA28-alpha and PA28-beta, which are induced by interferon-gamma (IFN-gamma), activate this latent enzyme complex. Genes encoding these activators, PSME1 and PSME2, respectively, have been characterized from various mammalian but only from zebrafish among piscine. We have cloned a PSME2 gene homologue from a leukocyte cDNA library of flounder, a marine fish. The flounder PSME2 gene (fPSME2) encompasses 1063 nucleotides and encodes a polypeptide of 242 amino acids (aa), with a deduced molecular weight of 27.2 kDa. The deduced protein has 82% sequence similarity to that of zebrafish and 73-74% sequence similarity to that of various mammalians and shows higher level sequence homology in the C-terminal region. There was a PA28-beta protein subunit-specific insert located at the corresponding to the KEKE motif of PA28-alpha protein. A phylogenetic tree derived using deduced amino acid sequences showed a diversion of piscine PSME2 from mammalian counterpart after diversion of PSME1 and PSME2 from a common ancestral gene. Northern blot analysis revealed a higher level expression of fPSME2 gene in kidney, spleen and muscle tissues of bacterial lipopolysaccharide (LPS) stimulated flounder than those from non-induced flounder.
Department of Microbiology, Pukyong National University, 599-1, Daeyeon 3-Dong, Nam-Gu, Busan 608-737, South Korea.
Dae-Hyun
DH
Kim
Sun-Me
SM
Lee
Bo-Young
BY
Hong
Young-Tae
YT
Kim
Tae-Jin
TJ
Choi
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary; D005432:Flounder / Q000235:genetics*; D008969:Molecular Sequence Data; D009124:Muscle Proteins / Q000235:genetics*; D010802:Phylogeny; D021122:Protein Subunits / Q000235:genetics; D011506:Proteins / Q000235:genetics*; D017422:Sequence Analysis, DNA; D029961:Zebrafish Proteins
D018076:DNA, Complementary; D009124:Muscle Proteins; D021122:Protein Subunits; D011506:Proteins; D029961:Zebrafish Proteins; C490051:psme1 protein, zebrafish; C490053:psme2 protein, zebrafish; C490054:psme3 protein, zebrafish