Sexual development in Cryptococcus neoformans

描述(由申请人提供)：这项建议的目标是确定在机会人类真菌病原体新生隐球菌中控制性发育的分子机制。性发育导致产生孢子，这些孢子可以散布到环境中。据认为，新生芽孢杆菌通过呼吸道途径从环境来源感染人类，在呼吸道途径中，真菌孢子被吸入肺泡。一旦被吸入，新生隐球菌会传播到中枢神经系统，并导致一种致命的脑膜炎。了解新生隐球菌性发育和产孢子的生物学，有望为预防和/或治疗隐球菌疾病提供有用的信息。这项研究也引起了普遍的兴趣，因为机会真菌是新出现的病原体：了解基本的真菌生物学为开发更有效的方法预防和治疗真菌疾病奠定了基础。在新生葡萄球菌中，性诱导基因SXI1a和SXI2a控制着性发育，但它们的作用机制尚不清楚。这项建议中概述的实验旨在阐明SXI1a和SXI2a调节基因表达以驱动性分化的机制。使用遗传学、生化、生物信息学和细胞生物学的方法，我们将1)通过识别和表征它们的下游靶标来定位由Sxi1a和Sxi2a控制的调节电路，2)通过评估它们的结构和功能之间的关系来确定控制性发育所需的Sxi1a和Sxi2a蛋白的性质，以及3)研究性发育所需的细胞过程，特别是双核丝状化。这里提出的不同方法将阐明性发育的早期阶段，并为新生隐孢子虫如何产生传染性颗粒提供新的见解。

DESCRIPTION (provided by the applicant): The goal of this proposal is to determine the molecular mechanisms by which sexual development is controlled in the opportunistic human fungal pathogen Cryptococcus neoformans. Sexual development results in the production of spores that can be dispersed into the environment. C. neoformans is thought to infect humans from environmental sources via a respiratory route in which fungal spores are inhaled into the alveoli of the lungs. Once inhaled, C. neoformans can disseminate to the central nervous system and cause a fatal form of meningitis. Understanding the biology of sexual development and spore production in C. neoformans promises to provide information useful in the prevention and/or treatment of cryptococcal disease. This study is also of general interest because opportunistic fungi are emerging pathogens: understanding basic fungal biology sets the stage for the development of more effective methods of preventing and treating fungal disease in general. In C. neoformans sexual development is controlled by the Sex Inducer genes, SXI1a and SXI2a, but the mechanism by which they act is unknown. The experiments outlined in this proposal are designed to elucidate the mechanism by which SXI1a and SXI2a regulate gene expression to drive sexual differentiation. Using genetic, biochemical, bioinformatic, and cell biological approaches we will 1) map the regulatory circuit controlled by Sxi1a and Sxi2a by identifying and characterizing their downstream targets, 2) establish the properties of the Sxi1a and Sxi2a proteins required to control sexual development by evaluating the relationships between their structures and functions, and 3) investigate the cellular processes required for sexual development with a specific focus on dikaryotic filamentation. The diverse approaches presented here will elucidate the early stages of sexual development and lend new insights into how infectious particle production occurs in C. neoformans.