Endosperm-specific demethylation and activation of specific alleles of alpha-tubulin genes of Zea mays L.

We have investigated the methylation status of the alpha-tubulin genes, and the degree of accumulation of their mRNAs in endosperm, embryo and seedling tissues of Zea mays L. We have found that many of the alpha-tubulin genes are differentially demethylated in the endosperm relative to the embryo and seedling. However, only for tub alpha 2 and tub alpha 4 could a correlation between DNA demethylation and increased RNA accumulation be detected. By analyzing the inbred lines W64A and A69Y and their reciprocal crosses, we have also identified in the endosperm two alpha-tubulin genes, tub alpha 3 and tub alpha 4, that are differentially demethylated if transmitted by the maternal germline, but that remain hypermethylated when transmitted by the paternal germline.