Evaluation of Protein Expression in Housekeeping Genes across Multiple Tissues in Rats

BACKGROUND: Housekeeping genes, which show constant protein expression patterns between different tissue types, are very important in molecular biological studies as an internal control for protein research. METHODS: The protein expression profiles of seven housekeeping genes (HPRT1, PPIA, GYS1, TBP, YWHAZ, GAPDH and ACTB) in various rat tissues (cerebrum, cerebellum, cardiac ventricle and atrium, psoas muscle, femoral muscle, liver, spleen, kidney, and aorta) were analyzed by Western blot and compared by coefficient of variation (CV). RESULTS: HPRT1 was stably expressed (CV≤10%) in six tissues (cerebrum, cerebellum, ventricle, femoral muscle, spleen, and kidney), PPIA was stably expressed in five tissues (cerebrum, cerebellum, ventricle, spleen and kidney), YWHAZ was stably expressed in three tissues (cerebrum, cerebellum, and kidney), and GAPDH was stably expressed in four tissues (cerebrum, ventricle, psoas muscle, and kidney). In comparison, GYS1, TBP, and ACTB were found to have CV values over 10% in all tissues. Of the seven genes examined, four (HPRT1, PPIA, YWHAZ, and GAPDH) were found to be stably expressed across multiple organs, with low CV values (≤10%). CONCLUSIONS: These results will provide fundamental information regarding internal controls for protein expression studies and can be used for analysis of postmortem protein degradation patterns in forensic medicine.