Characterization and expression of AmphiARF gene encoding a new member of ARF family from amphioxus Branchiostoma belcheri tsingtauense.

The cDNA AmphiARF, encoding a novel member of ARF family was for the first time identified from the gut cDNA library of amphioxus Branchiostoma becheri tsingtauense. The deduced amino acid sequence includes the motifs involved in GTP binding (DVGG, NKQD and SAK) and hydrolysis (GXDXXGK), and a glycine at position 2 for N-terminal myristoylation, which are all characteristic of ARFs. However, it has a 46 amino acid C-terminal extension (positions 183-227), which was not found in any ARF family previously described including ARF-like proteins. This suggests that AmphiARF is a new member of ARF family, which was also supported by the phylogenetic analysis. It is highly likely that the extended C-terminal of AmphiARF is a novel addition occurring after cephalochordate/vertebrate split. Northern blotting analysis revealed that AmphiARF transcript was present in all tissues examined, consistent with the involvement of ARFs in the fundamental role like vesicular trafficking of proteins.