Overview
Doctoral study program: Life Sciences
Supervisor: prof. Mgr. Richard Štefl, Ph.D.,
Topic title : Deciphering the Argonaute Loading Mechanisms in RNA-Silencing Pathways
Annotation:
Small RNAs are master regulators of gene expression in animals and plants. They guide Argonaute proteins to target RNAs, forming effector complexes that execute RNA silencing—an essential process for cellular homeostasis, development, and defense. Despite decades of research, the molecular principles governing Argonaute activation, guide-RNA loading, and strand selection remain poorly understood.
This PhD project aims to decipher the molecular mechanism of Argonaute loading using state-of-the-art electron cryomicroscopy (cryo-EM) combined with complementary biochemical and functional analyses. Building on our recent discoveries and concepts, we propose that two distinct loading pathways operate in mammals: one orchestrated by Dicer and another by HSP90–co-chaperone systems, both relying on negatively charged intrinsically disordered regions (IDRs) that have been largely overlooked in previous structural studies.
The student will determine high-resolution cryo-EM structures of key intermediates in these pathways—including Dicer–Argonaute–RNA and HSP90–co-chaperone–Argonaute–RNA assemblies—to visualize how conformational changes enable RNA transfer and strand selection.
By resolving this long-standing mechanistic puzzle, the project will define the molecular principles of Argonaute loading, shed light on the evolution and regulation of RNA silencing, and provide structural insights into the pathogenic mechanisms underlying AGO-related developmental disorders (AGO Syndrome).
Recommended literature:
1) Dicer structure and function: conserved and evolving features. Zapletal D, Kubicek, K, Svoboda P, Stefl R EMBO Reports (2023) 24:e57215 doi:10.15252/embr.202357215
2) microRNAs in action: biogenesis, function and regulation. Shang R, Lee S, Senavirathne G, Lai EC. Nat Rev Genet. 2023 doi:10.1038/s41576-023-00611-y.
Research area:
RNA/nucleic acids research in health
Keywords:
Argonaute loading; Cryo-electron microscopy (cryo-EM); RNA silencing mechanisms; Intrinsically disordered regions (IDRs); Dicer–HSP90 pathways
Funding of the PhD candidate:
GACR, OP JAK
In the academic year 2026/27 the net income of the CEITEC PhD School student is expected to be at least CZK 29,400 (approx. EUR 1215)
Requirements for candidate:
Biochemistry/molecular biology/structural biology
Information about the supervisor:
Prof. Richard Stefl is a leading structural biologist whose lab combines cryo-EM, NMR, and integrative structural biology to uncover how RNA–protein complexes control gene expression and cellular regulation. As an ERC grant holder and head of the CEITEC Centre for Structural Biology, he offers PhD students access to cutting-edge technologies, interdisciplinary mentoring, and an inspiring environment at the forefront of RNA biology and molecular mechanisms of gene silencing.
2 PhD students
11 absolvents
Research group info https://stefl-lab.ceitec.cz/
Start date: September 2026
Sign-up link: https://www.ceitec.eu/deciphering-the-argonaute-loading-mechanisms-in-rna-silencing-pathways/t11456
