Enhancement of reporter gene de novo methylation by DNA fragments from the alpha-fetoprotein control region.

摘要: The 5'-upstream region of the rat alpha-fetoprotein (AFP) gene strongly increased de novo methylation an adjacent chloramphenicol acetyltransferase (CAT) upon transfection into F9 mouse embryonal carcinoma cells. same effect was exerted by a distal 775-base pair (bp) fragment and 300- 1-kb fragments preceding transcriptional start site, but not other parts control region. Further division larger, active resulted in gradual decrease clonal variation patterns. 775-bp did depend on its orientation. It ablated insertion metallothionein I promoter between AFP CAT gene, upstream fragment. Two from increasing contained B1 B2 small interspersed repetitive elements, respectively. sequences different origin also acted to increase methylation. These findings support idea that mammalian genes contain specific involved regulating their effects these appear be cis, dependent proximity, orientation, require optimal size 500-700 bp. Small retrotransposon within such elements may particularly effective attracting