Roles for mRNA methylation and lncRNA in Candida mating and pathogenicity

描述（由申请人提供）：本提案旨在了解mRNA甲基化和长链非编码RNA这两种基因调控的分子机制在白色念珠菌毒力中的作用。白色念珠菌通常是一种良性共生菌，但可引起健康个体的皮肤和粘膜感染，以及易感个体的危及生命的全身感染。白色念珠菌的致病性与它从生长在酵母形式的细胞到生长在丝状和生物膜形式的转换能力有关。虽然它不能有性繁殖，但白色念珠菌可以通过交配产生遗传多样性，这有可能导致毒性和耐药性的增加。为了确定新的治疗途径，需要更好地了解这些过程背后的分子机制。mRNA甲基化在几十年前就被发现了，但这种大规模的修饰在其他真核生物中最近才变得明显，其在基因调控中的功能尚不清楚。在酿酒酵母中，IME4编码mRNA甲基转移酶，在酿酒酵母减数分裂和成丝过程中起调节作用。在白色念珠菌中存在IME4同源物。长链非编码RNA （lncRNA）是参与基因调控但不编码任何蛋白质的大型转录本。酿酒葡萄球菌IME4的表达受到反义lncRNA的调控，这种形式的调控似乎在白色念珠菌中保守。初步数据表明，在白色念珠菌中发生mRNA甲基化，并且IME4在丝化诱导条件下表达。此外，过表达IME4会抑制成丝。本研究将利用分子遗传学结合高通量RNA测序技术，鉴定白色念珠菌IME4 mRNA靶点，评估其在交配、成丝和生物膜形成中的作用，并研究lncRNA对其的调控作用。

DESCRIPTION (provided by applicant): This proposal is targeted at understanding the roles of mRNA methylation and long non-coding RNA, which are two molecular mechanisms of gene regulation, in Candida albicans virulence. C. albicans is a normally benign commensal, but can cause skin and mucosal membrane infections in healthy individuals, and life threatening systemic infections in susceptible individuals. C. albicans pathogenicity is linked to its ability o switch from growing in yeast-form cells to growing in filament and biofilm forms. While it cannot reproduce sexually, C. albicans can generate genetic diversity by mating, which has the potential to result in increased virulence and drug resistance. A better understanding of the molecular mechanisms behind these processes is required in order to identify new therapeutic avenues. mRNA methylation has been discovered decades ago, but the large scale of this modification in other eukaryotes has only recently became apparent, and its function in gene regulation is not yet understood. In Saccharomyces cerevisiae, IME4 encodes an mRNA methyltransferase, which plays a regulatory role in S. cerevisiae meiosis and filamentation. An IME4 homologue is present in C. albicans. Long non-coding RNA (lncRNA) are large transcripts that participate in gene regulation but do not encode any protein. S. cerevisiae IME4 expression is regulated by an antisense lncRNA, and this form of regulation appears to be conserved in C. albicans. Preliminary data indicates that mRNA methylation occurs in C. albicans, and that IME4 is expressed under filamentation inducing conditions. Furthermore, overexpression of IME4 inhibits filamentation. Using molecular genetics coupled with high throughput RNA sequencing, the proposed research will identify C. albicans IME4 mRNA targets, assess its role in mating, filamentation and biofilm formation, and study its regulation by lncRNA.