Identification and tissue-specific expression of amphioxus GM2 activator protein gene from amphioxus Branchiostoma belcheri.
An amphioxus cDNA, AmphiGM2AP, encoding GM2 activator protein was isolated from the gut cDNA library of Branchiostoma belcheri. It is 907 bp long, and its longest open reading frame codes for a precursor protein consisting of 242 amino acid residues with a signal peptide of 14 amino acids. The deduced amino acid sequence includes a conserved domain typical of GM2APs between residues 53 and 224, a single N-linked glycosylation site at position 65 and 8 conserved cysteines. Phylogenetic analysis showed that amphiGM2AP forms a club together with invertebrate GM2APs, indicating that AmphiGM2AP is evolutionarily closely related to invertebrate GM2APs rather than vertebrate ones. Both Northern blotting and in situ hybridization histochemistry analyses revealed a tissue-specific expression pattern of AmphiGM2AP in adult amphioxus with the strongest expression in the digestive system, which is in contrast to the widespread expression pattern of human, mouse and sheep GM2AP genes. It is suggested that AmphiGM2AP is possibly involved in the take-in of digested food components like lipid molecules.
Liu
Nai-Guo
NG
Laboratory 202, Department of Marine Biology, Ocean Universiy of China, 5 Yushan Road, Qingdao 266003, People's Republic of China. liunaiguo@yahoo.com.cn
Zhang
Shi-Cui
SC
Liu
Zhen-Hui
ZH
Liang
Yu-Jun
YJ
Xue
Ji-Yu
JY
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002816:Chordata, Nonvertebrate / Q000235:genetics*; D049289:G(M2) Activator Protein / Q000737:chemistry / Q000235:genetics*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D015723:Gene Library; D008969:Molecular Sequence Data; D016415:Sequence Alignment
D049289:G(M2) Activator Protein