The effect of dimethylnitrosamine on the synthesis of high-mobility group non-histone proteins in regenerating rat liver.
A single injection of dimethylnitrosamine (DMN) given to adult rats induces hepatocellular carcinoma if given during the period of restorative hyperplasia following partial hepatectomy. The effect of DMN on the sequence of biochemical events in regenerating liver is therefore of interest. As carcinogenesis is likely to involve a change in control of gene expression, and as evidence suggests that non-histone chromosomal proteins (NHP) are involved in gene control, the effect of DMN on synthesis of NHP in regenerating liver was studied. A well-defined group of NHP, the high mobility group (HMG), known to be specifically associated with DNA active in transcription, were investigated. Partial hepatectomy was found to cause a large increase in incorporation of [3H]lysine into HMG proteins; this did not occur immediately, but was apparent at the time of DNA synthesis and of mitosis. DMN did not alter the relative amounts of different HMG proteins in relation to histone H1, but the carcinogen caused a considerable reduction in incorporation of [3H]lysine. This decreased synthesis of the proteins which may function as gene derepressors may well be relevant in carcinogenesis.
D000818:Animals; D002868:Chromosomal Proteins, Non-Histone / Q000096:biosynthesis*; D004128:Dimethylnitrosamine / Q000494:pharmacology*; D005260:Female; D006498:Hepatectomy; D006609:High Mobility Group Proteins; D006657:Histones / Q000096:biosynthesis; D008099:Liver / Q000378:metabolism*; D008115:Liver Regeneration / Q000187:drug effects*; D051381:Rats
D002868:Chromosomal Proteins, Non-Histone; D006609:High Mobility Group Proteins; D006657:Histones; D004128:Dimethylnitrosamine