Methylation pattern of the bovine leukemia provirus genome in bovine leukemic cells

All the known genes of the bovine leukemia proviral genome were found to be heavily methylated in both fresh and short-term-cultured leukemic cells, the latter of which expressed viral antigens. However, the pXBL region appeared to be mostly demethylated or at least hypomethylated in both cells, indicating that there is a non-uniform methylation pattern of the proviral genome.