The pattern of methylation in rearranged and germ-line human immunoglobulin constant mu genes

Human C mu genes show two different patterns of demethylation. The first is associated with gene expression; this pattern is restricted to productive C mu alleles and is detected in leukemic and normal B-lymphocytes but not in T-lymphocytes, granulocytes or fibroblasts. The second pattern, not related with gene expression, is observed in B-lymphocytes, fibroblasts and part of T-lymphocytes but not in granulocytes.