Soukup Alexandra A, Fischer Gregory J, Luo Jerry, Keller Nancy P
Department of Genetics, University of Wisconsin-Madison, WI, United States.
Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, WI, United States.
Fungal Genet Biol. 2017 Mar;100:13-21. doi: 10.1016/j.fgb.2017.01.004. Epub 2017 Jan 9.
P bodies and stress granules are RNA-containing structures governing mRNA degradation and translational arrest, respectively. Saccharomyces cerevisiae Pbp1 protein localizes to stress granules and promotes their formation and is involved in proper polyadenylation, suppression of RNA-DNA hybrids, and preventing aberrant rDNA recombination. A genetic screen for Aspergillus nidulans mutants aberrant in secondary metabolism identified the Pbp1 homolog, PbpA. Using Dcp1 (mRNA decapping) as a marker for P-body formation and FabM (Pab1, poly-A binding protein) to track stress granule accumulation, we examine the dynamics of RNA granule formation in A. nidulans cells lacking pub1, edc3, and pbpA. Although PbpA acts as a functional homolog of yeast PBP1, PbpA had little impact on either P-body or stress granule formation in A. nidulans in contrast to Pub1 and Edc3. However, we find that PbpA is critical for sexual development and its loss increases the production of some secondary metabolites including the carcinogen sterigmatocystin.
P小体和应激颗粒是分别控制mRNA降解和翻译停滞的含RNA结构。酿酒酵母Pbp1蛋白定位于应激颗粒并促进其形成，且参与适当的多聚腺苷酸化、抑制RNA-DNA杂交以及防止异常的核糖体DNA重组。对构巢曲霉次级代谢异常的突变体进行的遗传筛选鉴定出了Pbp1的同源物PbpA。使用Dcp1（mRNA去帽）作为P小体形成的标志物，以及FabM（Pab1，多聚A结合蛋白）来追踪应激颗粒的积累，我们研究了缺乏pub1、edc3和pbpA的构巢曲霉细胞中RNA颗粒形成的动态过程。尽管PbpA作为酵母PBP1的功能同源物，但与Pub1和Edc3相比，PbpA对构巢曲霉中P小体或应激颗粒的形成几乎没有影响。然而，我们发现PbpA对有性发育至关重要，其缺失会增加包括致癌物柄曲霉素在内的一些次级代谢产物的产量。
