The S-TKs domain of Astragalus sinicus gene nip43 was cloned into pGBKT7 and used as a bait plasmid.17 original positive candidate clones were obtained with yeast two-hybrid screening method.One positive clone encoding an EPN protein out of importance was identified through sequencing the cDNA inserts.EPN is an adaptor in the polymerization of clathrins.The critical interaction domain of EPN with Nip43 was determined as ENTH/ANTH domain.Results of real-time qPCR showed that epn gene was involved in the early process of root nodulation.