DNMT3L enables accumulation and inheritance of epimutations in transgenic Drosophila.

Amitava Basu,Rakesh Kumar Mishra,Archana Tomar,Vasanthi Dasari,Sanjeev Khosla

doi:10.1038/srep19572

Abstract

DNMT3L is an important epigenetic regulator in mammals, integrating DNA methylation and histone modification based epigenetic circuits. Here we show DNMT3L to be a part of the machinery that enables inheritance of epigenetic modifications from one generation to the next. Ectopic expression of DNMT3L in Drosophila, which lacks DNMT3L and its normal interacting partners DNMT3A and DNMT3B, lead to nuclear reprogramming that was gradual and progressive, resulting in melanotic tumors that were observed only when these flies were maintained for five generations. This global gene expression misregulation was accompanied by aberrations in the levels of H3K4me3 and H3K36me3, globally as well as at specific gene promoters. The levels of these epigenetic aberrations (epimutations) also increased progressively across successive generations. The accumulation and inheritance of epimutations across multiple generations recapitulates the important role of DNMT3L in intergenerational epigenetic inheritance in mammals.

Highlights

DNMT3L is an important epigenetic regulator in mammals, integrating DNA methylation and histone modification based epigenetic circuits
We wanted to probe whether the interactions of DNMT3L with DNMT3A/3B on one hand and histone H3 on the other were redundantly influencing a common subset of genes or whether each of these interactions influenced a different subset of genes
Tissue-specific expression of DNMT3L was achieved by crossing these transgenic DNMT3L flies to GMR-GAL4 and hml-GAL4 (Hemolymph-specific) driver stock flies

Summary

Introduction

DNMT3L is an important epigenetic regulator in mammals, integrating DNA methylation and histone modification based epigenetic circuits. Ectopic expression of DNMT3L in Drosophila, which lacks DNMT3L and its normal interacting partners DNMT3A and DNMT3B, lead to nuclear reprogramming that was gradual and progressive, resulting in melanotic tumors that were observed only when these flies were maintained for five generations. This global gene expression misregulation was accompanied by aberrations in the levels of H3K4me[3] and H3K36me[3], globally as well as at specific gene promoters. The interaction of DNMT3L with histone H3 in the absence of de novo DNA methyltransferases could either be examined in mammals (mice or cell lines) deleted for DNMT3A and 3B or in an organism that normally lacks these proteins. Epimutations were passed onto the generation only by the mother, emphasizing the importance of DNMT3L in the establishment of parent-of-origin-specific epigenetic inheritance in mammals

Methods

Results

Conclusion