Gene Expression During Sporulation

描述（由申请人提供）：本提案重点关注枯草芽孢杆菌如何形成孢子。B。枯草芽孢杆菌因其易于遗传操作而成为研究孢子形成和原核生物细胞分化的范例。B的所有关键调节器。枯草芽孢杆菌孢子形成也见于包括病原体B的其它孢子形成物种中。炭疽、破伤风梭菌、C.产气荚膜梭菌C.肉毒杆菌和C.艰难梭菌，炭疽，破伤风，气性坏疽，肉毒杆菌中毒和结肠炎的原因后，抗生素治疗。高抗性的孢子对这些物种在自然界中的生存至关重要。结论来自对B的研究。枯草芽孢杆菌对这些物种具有普遍有效性。孢子的形成包括一个特征性的分裂过程，分裂成两种不同的细胞类型，即母细胞和前孢子。前孢子被母细胞吞噬并发育成成熟孢子。孢子的形成需要四个RNA聚合酶因子的作用，？F，然后？G在前孢子和？然后呢？K在母细胞中。它提出了发育生物学的一个基本问题：基因表达如何与形态变化相协调？该提案针对这一问题。什么时候？前孢子发出的F-导向信号来激活？E在母细胞中被延迟，采取了一种新的发育途径，其中在一个母细胞中形成两个孢子。这一行为开启了关于孢子形成过程中染色体复制和生长是如何控制的研究。它有助于研究同一种群中遗传相同的生物体如何遵循不同的发育路径。易位的染色体进入前孢子以下激活？F.有人建议研究如何完成易位导致吞噬的前孢子母细胞和激活？G在被吞没的前孢子中。公共卫生相关性：这一建议集中在枯草芽孢杆菌孢子形成过程中基因表达如何与形态变化相协调的基本问题上。所有关键的孢子形成调控基因也在相关病原体中发现，包括B。炭疽、破伤风梭菌、C.产气荚膜梭菌C.肉毒杆菌和C.很难重点放在如何改变信号的时机可以改变所采取的发展路径。

DESCRIPTION (provided by applicant): This proposal focuses on how spores are formed by Bacillus subtilis. B. subtilis has become a paradigm for the study of spore formation, and of cell differentiation in prokaryotes, because of the ease of its genetic manipulation. All the key regulators of B. subtilis spore formation are also found in other spore forming species including the pathogens B. anthracis, Clostridium tetani, C. perfringens, C. botulinum and C. difficile, the causes of anthrax, tetanus, gas gangrene, botulism and colitis following antibiotic therapy, respectively. The highly resistant spores are critical to the survival of theses species in nature. Conclusions from a study of B. subtilis will have general validity for these species. Spore formation involves a characteristic division into two different cell types, the mother cell and the prespore. The prespore is engulfed by the mother cell and develops into the mature spore. Spore formation requires the action of four RNA polymerase factors, ?F and then ?G in the prespore and ?E and then ?K in the mother cell. It presents a fundamental problem of developmental biology: how is gene expression coordinated with morphological change? The proposal addresses this problem. When the ?F-directed signal from the prespore to activate ?E in the mother cell is delayed, a novel developmental path is taken, in which two spores are formed within one mother cell. This behavior opens up the proposed study of how chromosome replication and growth are controlled during sporulation. It facilitates a study of how genetically identical organisms in the same population can follow different developmental paths. Translocation of the chromosome into the prespore follows activation of ?F. It is proposed to study how completion of translocation leads to engulfment of the prespore by the mother cell and activation of ?G in the engulfed prespore. PUBLIC HEALTH RELEVANCE: This proposal focuses on the fundamental problem of how gene expression is coordinated with morphological changes during formation of spores by Bacillus subtilis. All the key sporulation regulatory genes are also found in related pathogens, including B. anthracis, Clostridium tetani, C. perfringens, C. botulinum and C. difficile. Emphasis is placed on how altering the timing of signaling can change the developmental path taken.