DNA methylation plays an important role in promoter choice and protein production at the mouse Dnmt3L locus

What is it about?

This study was focused on interrogating the function of various sex specific isoforms of a vital developmental gene, Dnmt3L. The DNA Methyltransferase 3-Like (Dnmt3L) protein is a crucial cofactor in the germ line for the de novo methyltransferase Dnmt3a, which establishes imprints and represses transposable genetic elements, largely through methylating DNA. DNA methylation plays a crucial role in transcriptionally repressing certain classes of developmentally important genes, including imprinted genes.

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Why is it important?

Highlights - The Dnmt3L protein is required for DNA methylation in germ cells - Dnmt3L has three promoters, active in stem cells (Dnmt3Ls), adult testis (Dnmt3Lat) or oocytes (Dnmt3Lo) - Switching to Dnmt3Lat shuts down protein production in adult testis - Dnmt3Lo and Dnmt3Ls both produce proteins - The Dnmt3Ls promoter is itself methylated in oocytes - Repression and methylation of Dnmt3Ls are lost in Dnmt3L-/- ovaries - Dnmt3Ls is shut down prior to the completion of imprinting in oocytes - This explains the requirement for Dnmt3Lo in oocytes