Research of functional segments of chicken B-FA molecule binding with Ii chain / 中国免疫学杂志

ABSTRACT

Objective: To research the functional segments of B-FA molecule binding invariant chain and their characters. Methods:The DNA segments (α1α2, sα1α2 and α3TC ) of B-FA genes were respectively cloned and inserted into prokaryotic or eukaryotic expression plasmids,then they were singly or co-transfected with Ii gene into the engineering bacteria E. coli (BL-21)or 293T cells. After induction of expression,affinity chromatography and SDS-PAGE identification,the binding between B-FA segments and Ii molecule and co-localization in cells were observed with Pull-down and Western blot. Results:First three recombinant prokaryotic expression plasmids and four recombinant eukaryotic expression plasmids were constructed. The single molecules expressed by B-FA segments were observed after an affinity chromatography. Secondly the complexes of Ii/B-FA-α1α2 and Ii/B-FA-sα1α2 were detected by a Pull-down from the co-transfected corresponding prokaryotic expression plasmids,but no complex of Ii andα3TC,also in the western blot it was detected that B-FA-α1α2 or B-FA-sα1α2 as functional segment could bind Ii to form complex. Finally in eukaryotic expression 293T cells B-FA-sα1α2 kept localization, the same as B-FA. Conclusion: Chicken B-FA-α1α2 is function segment to bind with Ii molecule and keeps the location characters same as B-FA. The results of this research first time provide experimental evidence about B-FA functional region binding segment to Ii molecule.