Depletion of SMARCB1 and BRD7, two SWI/SNF chromatin remodelling complex subunits, differentially impact porcine embryo development.

Context: SWI/SNF chromatin remodelling complexes are composed of multiple protein subunits and can be categorised into three sub-families, including the BAF, PBAF, and GBAF complexes. We hypothesised that depletion of SMARCB1 and BRD7, two subunits unique to different SWI/SNF sub-families, would differentially impact porcine embryo development.

Aim: The aim of these experiments was to determine the developmental requirements of two SWI/SNF subunits, SMARCB1 and BRD7.

Nuclear trafficking dynamics of Bromodomain-containing protein 7 (BRD7), a switch/sucrose non-fermentable (SWI/SNF) chromatin remodelling complex subunit, in porcine oocytes and cleavage-stage embryos.

In the work presented here, we investigated how bromodomain-containing protein 7 (BRD7), a subunit associated with switch/sucrose non-fermentable (SWI/SNF) chromatin remodelling complexes, is trafficked between cellular compartments during embryo development. SWI/SNF complexes are multi-subunit complexes that contain a core catalytic subunit (SWI/SNF related, Matrix associated, Actin dependent Regulator of Chromatin, subfamily A, member 4, or member 2; SMARCA4 or SMARCA2) and a collection of additional subunits that guide the complexes to their appropriate loci; BRD7 is one of these additional subunits. We hypothesised that BRD7 is exported from the nuclei of porcine oocytes and embryos in a Chromosome Region Maintenance 1 (CRM1)-dependent manner and imported into the nuclei using the karyopherin α/β1 heterodimer.

Differential expression of key subunits of SWI/SNF chromatin remodeling complexes in porcine embryos derived in vitro or in vivo.

In vitro embryo production is an established method for both humans and animals, but is fraught with inferior development and health issues in offspring born after in vitro fertilization procedures. Analysis of epigenetic changes caused by exposure to in vitro conditions should shed light on potential sources of these phenotypes. Using immunocytochemistry, we investigated the localization and relative abundance of components associated with the SWI/SNF (Switch/Sucrose non-fermentable) chromatin-remodeling complex-including BAF155, BAF170, BAF180, BAF53A, BAF57, BAF60A, BAF45D, ARID1A, ARID1B, ARID2, SNF5, and BRD7-in oocytes and in in vitro-produced and in vivo-derived porcine embryos.