OBJECTIVETo investigate the effect of immunization with prokaryotically expressed recombinant fusion protein of extracellular near-transmembrane domain of Tibet minipig leptin receptor (OBR) on fat deposition in SD rats.

METHODSA pair of specific primers containing BamHI and HindIII restriction enzyme sites was designed to amplify the extracellular near-transmembrane domain (1705-2364 bp) of Tibet minipig OBR gene. After digestion, the amplified fragment was inserted into the plasmid pRSETA between BamHI and HindIII sites. The recombinant plasmid was transformed and expressed in E.coli BL21(DE3) and the product was analyzed by SDS-PAGE and Western blotting. SD rats were immunized with the fusion protein, and the changes in body weight, feed intake, body length, Lee's index, percentage of abdominal fat, liver fat deposition and subcutaneous fat deposition were assessed.

RESULTSThe recombinant fusion protein obtained (about 27.6 kD) was expressed in E.coli induced by IPTG and identified by SDS-PAGE and Western blotting. The rats immunized with the fusion protein showed no significant changes in body weight, body length, Lee's index, percentage of abdominal fat or liver fat deposition as compared with the control rats. Nevertheless, the immunization caused significantly increased feed intake and significantly decreased volume of subcutaneous fat cells.

CONCLUSIONImmunization with the fusion protein of extracellular near-transmembrane domain of Tibet minipig OBR can promote feed intake and suppress subcutaneous fat deposition in SD rats.