부산대학교 도서관

Proper transcription orchestrated by RNA polymerase II (RNPII) is crucial for cellular development, which is rely on the phosphorylation state of RNPII's carboxyl-terminal domain (CTD). Sporangia, developed from mycelia, are essential for the destructive oomycetes Phytophthora, remarkable transcriptional changes are observed during the morphological transition. However, how these changes are rapidly triggered and their relationship with the versatile RNPII-CTD phosphorylation remain enigmatic. Herein, we found that Phytophthora capsici undergone an elevation of Ser5-phosphorylation in its uncanonical heptapeptide repeats of RNPII-CTD during sporangia development, which subsequently changed the chromosomal occupation of RNPII and primarily activated transcription of certain genes. A cyclin-dependent kinase, PcCDK7, was highly induced and phosphorylated RNPII-CTD during this morphological transition. Mechanistically, a novel DCL1-dependent microRNA, pcamiR1, was found to be a feedback modulator for the precise phosphorylation of RNPII-CTD by complexing with PcAGO1 and regulating the accumulation of PcCDK7. Moreover, this study revealed that the pcamiR1-CDK7-RNPII regulatory module is evolutionarily conserved and the impairment of the balance between pcamiR1 and PcCDK7 could efficiently reduce growth and virulence of P. capsici. Collectively, this study uncovers a novel and evolutionary conserved mechanism of transcription regulation which could facilitates correct development and identifies pcamiR1 as a promising target for disease control. Author summary: Ser5 phosphorylation (S5p) on the carboxyl-terminal domain of RNA polymerase II (RNPII-CTD) is essential for RNPII activation and enables it properly transcribes genes. Sporangium is dispensable for the development and infection of Phytophthora, it differentiates from hypha rapidly and undergoes remarkable transcriptional changes during the morphological transition. However, the regulatory machinery of the changes and the role of RNPII-CTD-Ser5p in the transition remain a mystery. Herein, a novel microRNA-involved module, pcamiR1-CDK7-RNPII, which could rapidly and precisely ensures transcriptional plasticity by regulating the phosphorylation of an uncanonical heptapeptide repeats of RNPII-CTD is reported. The discoveries could broaden the understanding of transcriptional regulation through a novel way, also could strongly benefit the control of many human and plant diseases based on the evolutionary conserved microRNA with a safe and convenient way. [ABSTRACT FROM AUTHOR]