OBJECTIVETo screen the proteins interacting with inhibitor of differentiation 1(Id1) using yeast two-hybrid analysis in adult human lung cDNA libraries.

METHODSThe coding sequence of Id1 was amplified by PCR and cloned into the bait plasmid. The recombinant bait vector pHybLex/Zeo-Id1 was verified by restriction endonuclease digestion before transformation into the yeast strain EGY48/pSH18-34, which was tested subsequently for reporter genes Leu2 and LacZ activation. The pHybLex/Zeo-Id1 plasmid and the cDNA library plasmid were sequentially transformed into the yeast strains and screened to obtain Leu2(+) and Leu2(+)LacZ(+) clones, with the false positive clones excluded using positive and negative controls, and the plasmid of the true positive clone was sequenced and blasted for homological analysis.

RESULTSSuccessful construction of pHybLex/Zeo-Id1 was confirmed by enzyme digestion. After transformation of pHybLex/Zeo-Id1 into EGY48/pSH18-34, no specific reporter genes Leu2 and LacZ activation was found. The pHybLex/Zeo-Id1 plasmid and the cDNA library plasmid were sequentially transformed into yeast strain, and 198 Leu(+) clones and 19 Leu(+)LacZ(+) double positive clones were obtained. After elimination of the false positive clones, one true positive clone was obtained, whose plasmid analysis by sequencing and blasting indicated high homology (99.5%, 556/559) to AGGF1 (an angiogenic factor with G-patch and FHA domains 1). AGGF1 expression was confirmed in the true positive yeast cells by Western blotting.

CONCLUSIONAGGF1 is confirmed to interact with Id1 by yeast two-hybrid analysis for screening adult human lung cDNA libraries.