Figure 1.
Mice possessing a heterozygous deletion of the PTG gene display reduced PTG protein levels while the expression of GL and GM are not altered. (a) The entire 1-kb coding region of the intronless PTG gene was targeted for disruption. PTG heterozygous mice were generated as outlined in Methods and then backcrossed for five generations to inbred C57BL/6J mice. (b) PTG protein levels are reduced in insulin-responsive tissues of PTG+/– mice. Tissue homogenates were prepared from nonfasted 1- to 2-month-old male animals and analyzed by Western blotting. Equivalent loading was insured by analysis of the levels of the basal transcription factor TFIIEα. (c) The expression levels of the tissue-specific glycogen-targeting subunits GM and GL are unchanged in PTG heterozygous mice. The expression level of GL at the mRNA level was analyzed by RT-PCR using liver total RNA isolated from nonfasting 1- to 2-month-old male animals. The expression of GM was analyzed by Western blotting and equivalent loading was insured by analysis of the levels of TFIIEα.