MADS-box transcriptional regulation of dimorphic transition in Penicillium marneffei

马尔尼菲青霉二态性转变的 MADS-box 转录调控

• 批准号: 9169300
• 负责人: James Jing Cai
• 金额: $ 21.63万
• 依托单位: TEXAS A&M AGRILIFE RESEARCH
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-06-27 至 2018-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9169300
• 关键词: Acquired Immunodeficiency Syndrome; Acute; Anemia; Area; Body Temperature; Boxing; Cells; ChIP-seq; DNA; Data; Development; Diagnostic; Evolution; Family; Fever; Foundations; Future; Gene Deletion; General Population; Genes; Genetic; Genomic Segment; Genomics; Goals; Growth; HIV Infections; Hospital Mortality; Hyphae; Immune; Immunocompromised Host; Immunosuppression; Individual; Infection; Investigation; Knowledge; Link; Liver; Maps; Methods; Molecular; Morphogenesis; Mutation; Mycoses; Pathogenicity; Penicillium; Phase; Phase Transition; Play; Process; Public Health; Regulator Genes; Reporting; Research; Role; Southeastern Asia; Swelling; System; Techniques; Temperature; Testing; Therapeutic; Transcriptional Regulation; Work; Yeasts; base; dimorphism; effective intervention; expectation; fungus; gain of function; genome sequencing; innovation; latent infection; loss of function; loss of function mutation; lymph nodes; mortality; mouse model; mutant; novel; overexpression; pathogen; prevent; skin lesion; transcription factor; transcriptome sequencing; transmission process; whole genome

Systemic dimorphic fungi collectively cause over one million new infections every year. Latent infections worldwide grow to the tens of millions, making them a priority for today's research. Penicillium marneffei (Pm) is of particular concern due to a marked increase in the number of cases of penicilliosis in the last 20 years, which has been concurrent with the rise in immunosuppression due to the global spread of HIV infections. Pm grows as hypha in its environmental reservoir and as yeast in mammalian hosts. The phase transition between the two growth forms is considered to be essential for its pathogenicity and the transmission of penicilliosis. The transition between hypha and yeast is reversible and can be triggered at a sharp threshold temperature of 37°C. The precise mechanisms underlying the thermosensing and the phase transition in Pm remain unknown. Therefore, there is a critical need to identify key genes and regulatory processes involved in the morphogenetic control in Pm. The applicants' recent findings provide a promising, new opportunity for target identification. Using an innovative, serial culture-based experimental evolution (EE) technique, the applicants derived mutant Pm strains that undergo the hypha-to-yeast phase transition at 30°C rather than 37°C. DNA- and RNA- sequencing of the mutant and wild-type strains revealed important roles of a family of MADS-box transcription factor (TF) genes, especially madsB and madsA, in regulating thermal dimorphism in Pm. The expression of madsB in wild type is up-regulated 1,500-fold during the hypha-to-yeast transition. The madsB loss-of-function mutation caused by genomic deletion in mutant strains seems to be responsible for the lower threshold temperature of phase transition. Significantly, EE-derived mutants are found to be completely avirulent in the mouse model, suggesting that the precise threshold temperature at 37°C for the phase transition is essential for Pm to infect and/or adapt to the host condition. Furthermore, the overexpression of madsA causes Pm to grow as hypha instead of yeast at 37°C. These preliminary data led to the central hypothesis that the Pm thermosensing systems act through temperature-responsive activities of the MADS-box TFs. Based on these preliminary results, the applicants propose the following two Specific Aims: (1) determine the roles of madsB and madsA in regulating thermal dimorphism in Pm, and (2) identify the downstream targets of MadsB and MadsA. Upon completion of the proposed research, the applicants expect to critically test the functions of the two MADS-box TFs in regulating dimorphic development in Pm (Aim 1). The applicants will identify the downstream targets of MadsB and/or MadsA, and examine the functions of selected targets in Pm (Aim 2). Together, these results will provide much-needed entry points to further investigate the otherwise mysterious mechanisms underlying thermal dimorphism in this important but understudied fungal pathogen.

系统性二型真菌每年共同导致超过一百万的新感染。潜伏感染 世界范围内增长到数千万，使他们成为当今研究的重点。马尔尼菲青霉菌（Pm） 由于在过去20年中青霉病的病例数量显著增加， 这与由于HIV感染的全球传播而引起的免疫抑制的增加同时发生。下午 在环境中以菌丝生长，在哺乳动物宿主中以酵母生长。之间的相变 这两种生长形式被认为是其致病性和传播青霉病所必需的。 菌丝和酵母之间的转变是可逆的，并且可以在2.5 ℃的急剧阈值温度下触发。 37摄氏度。温度敏感和相变的精确机制仍然未知。 因此，迫切需要鉴定参与形态发生的关键基因和调控过程。 控制在PM。申请人最近的发现为目标识别提供了一个有希望的新机会。 使用创新的、基于连续培养的实验进化（EE）技术，申请人获得了突变体 在30°C而不是37°C下经历菌丝-酵母相变的Pm菌株。DNA和RNA 突变株和野生型菌株的测序揭示了MADS盒转录家族的重要作用 转录因子（TF）基因，尤其是madsB和madsA，在调节Pm的热二型性中起重要作用。的表达 野生型的madsB在菌丝到酵母的转变过程中上调了1,500倍。madsB功能丧失 突变株中基因组缺失引起的突变似乎是导致阈值较低的原因 相变温度。值得注意的是，EE衍生的突变体被发现是完全无毒的， 小鼠模型，表明相变的精确阈值温度为37°C是必不可少的 使Pm感染和/或适应宿主条件。此外，madsA的过表达导致Pm 在37°C下以菌丝而不是酵母生长。这些初步数据导致了一个中心假设，即PM 热敏系统通过MADS盒TF的温度响应活动起作用。基于这些 初步结果，申请人提出以下两个具体目标：（1）确定madsB的作用 和madsA在调节Pm中的热二型性中的作用，以及（2）鉴定MadsB和 MadsA.在完成拟议的研究后，申请人希望严格测试 两个MADS盒转录因子在调节Pm二型发育中的作用（目的1）。申请人将确定 MadsB和/或MadsA的下游靶标，并检查Pm中所选靶标的功能（目的2）。 总之，这些结果将提供急需的切入点，以进一步调查其他神秘的 这种重要但尚未充分研究的真菌病原体的热二型性机制。