Departamento de Genética del Desarrollo y Fisiología Molecular. Instituto de Biotecnología, Universidad Nacional Autónoma de México, Avenida Universidad 2001, Cuernavaca, 62210, Morelos, Mexico.
Institute of Biology, Leiden University, Leiden, 2333 BE, The Netherlands.
Sci Rep. 2018 Oct 18;8(1):15369. doi: 10.1038/s41598-018-33746-8.
SWI/SNF or BAF chromatin-remodeling complexes are polymorphic assemblies of homologous subunit families that remodel nucleosomes and facilitate tissue-specific gene regulation during development. BAF57/SMARCE1 is a BAF complex subunit encoded in animals by a single gene and is a component of all mammalian BAF complexes. In vivo, the loss of SMARCE1 would lead to the formation of deficient combinations of the complex which might present limited remodeling activities. To address the specific contribution of SMARCE1 to the function of the BAF complex, we generated CRISPR/Cas9 mutations of smarce1 in zebrafish. Smarce1 mutants showed visible defects at 72 hpf, including smaller eyes, abnormal body curvature and heart abnormalities. Gene expression analysis revealed that the mutant embryos displayed defects in endocardial development since early stages, which led to the formation of a misshapen heart tube. The severe morphological and functional cardiac problems observed at 4 dpf were correlated with the substantially increased expression of different cardiac transcription factors. Additionally, we showed that Smarce1 binds to cis-regulatory regions of the gata5 gene and is necessary for the recruitment of the BAF complex to these regions.
SWI/SNF 或 BAF 染色质重塑复合物是同源亚基家族的多态组装体，可重塑核小体，并在发育过程中促进组织特异性基因调控。BAF57/SMARCE1 是一种 BAF 复合物亚基，在动物中由单个基因编码，是所有哺乳动物 BAF 复合物的组成部分。在体内，SMARCE1 的缺失会导致复合物的缺陷组合形成，这可能会导致有限的重塑活性。为了确定 SMARCE1 对 BAF 复合物功能的具体贡献，我们在斑马鱼中生成了 CRISPR/Cas9 突变 smarce1。Smarce1 突变体在 72 hpf 时表现出明显的缺陷，包括眼睛变小、身体弯曲异常和心脏异常。基因表达分析显示，突变胚胎在早期就表现出心内膜发育缺陷，导致心脏管腔畸形。在 4 dpf 时观察到的严重形态和功能心脏问题与不同心脏转录因子的表达显著增加相关。此外，我们还表明 Smarce1 结合 gata5 基因的顺式调控区域，并且对于 BAF 复合物在这些区域的募集是必需的。
