geminin调控胰腺特化的分子机理研究

Our preliminary data indicate that loss-of-geminin in zebrafish results in significant increases in the expression of pancreas specification marker pdx1. Our and other labs have previously reported direct interactions of geminin with the Polycomb group member Scmh1 and the SWI/SNF complex member Brg1. Therefore, we raise the hypothesis that geminin associates with genomic DNA elements at the pancreas specification regulatory region via Scmh1 or Brg1, thus playing an important part in pancreas development. To verify our hypothesis and investigate mechanisms of pancreas specification regulated by geminin, this project is divided into five parts: 1) Identification of the geminin-associated genomic DNA elements. 2) Characterization of genes that mediates roles of geminin in pancreas specification. 3) Establishment of single cell lineage map for endodermal cells at the 4-somite stage to identify early specified pancreatic cell populations. 4) Regulatory mechanisms of pancreas specification the geminin mediator gene. 5) Regulatory mechanisms of mediator gene transcription by geminin through Scmh1 or Brg1.

本项目前期工作中发现斑马鱼胚胎中细胞周期调控因子geminin敲降会导致胰腺特化分子标记pdx1的表达大量增加。申请人及其他实验室曾报道geminin与Polycomb复合体成员Scmh1及SWI/SNF复合体成员Brg1直接相互作用。由此，我们提出geminin通过Scmh1或Brg1附着在染色质特定的胰腺特化基因区域、调控该基因的转录进而在胰腺特化中发挥重要功能的假说。为证实该假说并阐明geminin调控胰腺特化的详细分子机理，本项目将开展以下五项工作：1）geminin在染色质DNA附着位点的克隆；2）附着位点区域胰腺特化功能基因的鉴定及geminin对其转录活性的调控研究；3)建立4体节时期内胚层细胞单细胞分辨率谱系定位图谱以定位早期特化胰腺细胞；4）介导geminin作用的功能基因调控胰腺特化的分子机制；5）geminin通过Scmh1或Brg1调控胰腺特化功能基因转录的分子机制

本项目取得了以下三项重要研究进展：1）建立了斑马鱼早期内胚层单细胞分辨率谱系图谱；2）获得了多个早期内胚层中各消化器官前体细胞谱系发生和命运决定的重要调控因子，初步揭示其发挥功能的分子机制；3）揭示了胰腺前体细胞分裂能力通过geminin与胰腺命运决定的联系机制。项目取得的进展中，有两项已分别投稿到Nature Cell Biology和Developmental Cell，并都在审稿过程中。