Transcriptional repression of repeat-derived transcripts correlates with histone hypoacetylation at repetitive DNA elements in aged mice brain

In order to better characterize epigenetic alterations at repetitive DNA elements with aging, DNA methylation and histone marks at various repeat classes were investigated. Repetitive DNA elements were hypermethylated in the brains of old mice. Histone hypoacetylation and altered histone trimethylation at repetitive sequences were detected in brain tissues during aging. The expression of repeat-derived transcripts (RDTs) was then measured to explore any correlations with the observed epigenetic alterations. Large numbers of RDTs investigated were down-regulated along with age. Bisulfite sequencing revealed that CpG dinucleotide methylation patterns at the repeats of the RDT promoter region were mostly well maintained during aging. ChIP assay showed that histones were deacetylated at the promoter region of RDTs in aged mice brain. The observations indicate that the transcriptional repression of RDTs appears to be related to histone hypoacetylation, but not to DNA hypermethylation at repeat DNA elements in the brains of aged mice.

► Poly(A)-binding protein (Pabp) is in a complex with Bic-D.
► pabp interacts genetically with Bic-D and osk.
► pabp is essential for oocyte growth, and for stability and localization of osk.
► Pabp binds specifically to A-rich sequences (ARS) in the osk 3′UTR.
► osk 3′UTR ARS are required in vivo for osk function during early oogenesis.