Counts J L, Goodman J I
Department of Pharmacology and Toxicology, Michigan State University, East Lansing 48824-1317.
Cancer Lett. 1993 Dec 10;75(2):129-36. doi: 10.1016/0304-3835(93)90197-h.
We examined the methylation status of the 5' flanking region of Ha-ras in the liver of the liver tumor-prone B6C3F1 male (C57BL/6 female x C3H/He male) and C3H/He male, plus the relatively resistant C57BL/6 male mouse strains. Southern analysis revealed the presence of CCGG sites methylated at the internal cytosine, as well as unmethylated CCGG sites in all three strains. Digestion with StyI and XhoI revealed an unmethylated XhoI site in the C57BL/6 male. This pattern is not obvious in the B6C3F1 or C3H/He, indicating sequence variation and/or less methylation of Ha-ras in those strains of mice that exhibit a high propensity towards development of liver tumors.
