Investigating the chromatin landscape of the early mammalian embryo is essential to understand how epigenetic mechanisms may direct reprogramming and cell fate allocation. Genome-wide analyses of the epigenome in preimplantation mouse embryos have recently become available, thanks to the development of low-input protocols. DNA adenine methyltransferase identification (DamID) enables the investigation of genome-wide protein-DNA interactions without the requirement of specific antibodies. Most importantly, DamID can be robustly applied to single cells. Here we describe the protocol for performing DamID in single oocytes and mouse preimplantation embryos, as well as single blastomeres, using a Dam-LaminB1 fusion to generate high-resolution lamina-associated domain (LAD) maps. This low-input method can be adapted for other proteins of interest to faithfully profile their genomic interaction, allowing us to interrogate the chromatin dynamics and nuclear organization during the early mammalian development.
Keywords: LADs; Low-input DamID; Mouse embryo; Nuclear organization; Single-cell genomics.