Transcription of the alpha2u-globulin gene in male rat liver nuclei in vitro.

Alpha2u-globulin is a male rat liver protein under multihormonal control which represents approximately 1% of hepatic protein synthesis. We have measured the rate of transcription of the alpha2u-globulin gene using a nuclear cell-free transcriptional system with mercurated CTP as substrate for the endogenous RNA polymerases. The newly synthesized, mercurated RNA was purified free of endogenous RNA by chromatography on sulfhydryl agarose and hybridized to 3H-labeled alpha2u-globulin cDNA. It was found that, in male rat liver nuclei, alpha2u-globulin RNA sequences represent 0.005% of the total newly synthesized RNA. Actinomycin D or alpha-amanitin completely blocks the synthesis of alpha2u-globulin RNA in these nuclei. No alpha2u-globulin RNA synthesis was detectable in female rat liver nuclei. Thus, within the limits of our detection the absence of hepatic alpha2u-globulin mRNA in female rats appears to be due to a lack of transcription of the alpha2u-globulin gene in these animals.