The interaction between RPAP3 and TRBP reveals a possible involvement of the HSP90/R2TP chaperone complex in the regulation of miRNA activity

Abstract

MicroRNAs silence mRNAs by guiding the RISC complex. RISC assembly occurs following cleavage of pre-miRNAs by Dicer, assisted by TRBP or PACT, and the transfer of miRNAs to AGO proteins. The R2TP complex is an HSP90 co-chaperone involved in the assembly of ribonucleoprotein particles. Here, we show that the R2TP component RPAP3 binds TRBP but not PACT. The RPAP3-TPR1 domain interacts with the TRBP-dsRBD3, and the 1.5 Å resolution crystal structure of this complex identifies key residues involved in the interaction. Remarkably, binding of TRBP to RPAP3 or Dicer is mutually exclusive. Additionally, we found that AGO(1/2), TRBP and Dicer are all sensitive to HSP90 inhibition, and that TRBP sensitivity is increased in the absence of RPAP3. Finally, RPAP3 seems to impede miRNA activity, raising the possibility that the R2TP chaperone might sequester TRBP to regulate the miRNA pathway.

Small RNA sequencing provides insights into molecular mechanism of flower development in Rhododendron pulchrum Sweet

“…MiRNAs (approximately 22 nt), a class of non-coding single strand molecules negatively regulating gene expressions both at transcriptional and posttranscriptional levels, play critical roles in biological processes, including embryogenesis and organ development 11 – 14 , and metabolism 15 – 18 . In particular, functional mature miRNAs could be incorporated into Argonaute 1 (AGO1)-containing RNA-induced silencing complex (RISC), and causing degradation or translational repression in sequence-specific manner 19 , 20 . The miRNAs often regulate corresponding mRNA targets through guiding cleavages between 10 and 11th nucleotides in complementary region 21 .…”

Molecular mechanism of flower color formation in Rhododendron simsii Planchon revealed by integration of microRNAome and RNAomics

“…MicroRNAs (miRNA), a class of non-coding single strand molecules negatively regulating gene expressions both at transcriptional and posttranscriptional levels via cleaving targets or repressing protein translation, play important roles in ower organ development (Takeda et al 2023; Allahverdy and Rashidi 2023). Particularly, functional mature miRNAs are incorporated into Argonaute 1 (AGO1)-containing RNA-induced silencing complex (RISC) target endogenous transcripts, and cause mRNA degradation or translational repression in a sequence-speci c manner (Abel et al 2022). The construction of miRNA-mRNA regulatory network could reveal key genes and pathways involved in ower color formation.…”

Small RNA Sequencing Provides Insights into Molecular Mechanism of Flower Development in Rhododendron Pulchrum Sweet

“…MiRNAs (approximately 22 nt), a class of non-coding single strand molecules negatively regulating gene expressions both at transcriptional and posttranscriptional levels via cleaving targets or repressing protein translation, play critical roles in biological processes, including embryogenesis and organ development (Wójcik and Gaj, 2016;Zhong et al 2017;Wang et al 2017;Xing et al 2022), metabolism (Liang et al 2017;Yang et al 2017), as well as tumorigenesis and chronic disease in animals (Sulas et al 2017;Khezri et al 2022). In particular, functional mature miRNAs could be incorporated into Argonaute 1 (AGO1)-containing RNA-induced silencing complex (RISC) target endogenous transcripts, and causing degradation or translational repression in sequence-specific manner (Zhang et al 2021;Abel et al 2022). The specific position of target AGO1 protein is often found between the 10 th and 11 th 4 nucleotides of target mRNA (Meyers et al 2008).…”