[Determination of the binding site of testis-specific nucleoporin BS-63 to transportin (karopherin beta 2) and the proof of their combination in vitro]

Abstract

Objective: To locate the binding site of testis-specific nucleoporin BS-63 to transportin (karopherin beta 2) and confirm their combination in vitro.

Methods: Constructed different fragments of C terminal BS-63 was employed to localize the binding site of the testis-specific nucleoporin BS-63 to transportin by yeast two-hybrid system technique pull-down test was used to identify the interaction between the purified expressed fragments of BS-63 0.6 K and transportin in vitro.

Results: BS-63 binding site to transportin was shortened from 1.6 kb to 0.6 kb which included a Ran binding domain (RanBD). SDS-PAGE and Western blot tests confirmed the recombinant purified protein coded by 0.6 kb fragment of BS-63 cDNA could interact with transportin in vitro.

Conclusions: In germ cells, the function of the testis-specific nucleoporin BS-63 localized at cytoplasmic side of NPC importing cargoes into nuclear may be accomplished by transportin cooperation.