# Guide RNA Binding Complex

> **NIH NIH R01** · BOSTON UNIVERSITY MEDICAL CAMPUS · 2020 · $499,707

## Abstract

ABSTRACT
Trypanosoma brucei species inflict health hazards and economic hardship on arguably the most marginalized
populations in the world. Some of the best-studied Excavata, trypanosomes also represent important models in
many areas of research, including antigenic variation, host-pathogen interaction, developmental reprogramming
and mitochondrial biology. This project will elucidate mechanisms by which macromolecular RNA editing
substrate binding complex (RESC) stabilizes and delivers mitochondrial pre-mRNAs and guide RNAs into the
U-insertion/deletion editing pathway, and coordinates polyadenylation and translation of edited mRNAs. We
establish the RESC platform as the RNA binding constituent of the editing holoenzyme and seek to investigate
its role in editing reactions, and functions beyond the RNA editing process. To this end, we demonstrate that
RESC-associated MERS1 pyrophosphohydrolase and KPAP1 poly(A) polymerase target pre-mRNA 5′ and 3′
ends, respectively. Importantly, both 5′ pyrophosphate removal and 3′ A-tailing appear to be critical for pre-mRNA
stabilization prior to editing. Conversely, specific module within RESC is suggested to couple the completion of
editing with post-editing 3′ A/U-tailing and mRNA binding to the ribosome. Collectively, the existing evidence
positions the ~25 polypeptide RESC complex as the multimodal nexus of mitochondrial RNA processing.
Furthermore, initial investigation of RESC-associated MERS1 complex, RNA polymerase (MTRNAP), and the 3′
processome (MPsome) challenges the long-standing model of multicistronic maxicircle transcription and
endonucleolytic partitioning of primary transcripts. The proposed experiments will deepen understanding of RNA
editing by determining the RESC structure at near-atomic resolution and RNA binding specificities of individual
subunits. We will test a broad functional hypothesis that discrete RESC modules coordinate completion of mRNA
editing with 3′ modification and translational activation. Finally, we put forward a fundamentally novel concept of
monocistronic pre-mRNAs that are transcribed from individual promoters and shaped by 5ʹ modification and
antisense RNA-controlled 3′-5′ degradation. By elucidating the RESC structure, RNA binding properties, and
higher-order interactions, and evaluating the paradigm-shifting “monocistronic hypothesis,” this program will
expand the knowledge of critical parasite-specific processes and may provide new drug targets.

## Key facts

- **NIH application ID:** 9961465
- **Project number:** 5R01AI101057-10
- **Recipient organization:** BOSTON UNIVERSITY MEDICAL CAMPUS
- **Principal Investigator:** Ruslan Afasizhev
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $499,707
- **Award type:** 5
- **Project period:** 2012-05-10 → 2022-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9961465

## Citation

> US National Institutes of Health, RePORTER application 9961465, Guide RNA Binding Complex (5R01AI101057-10). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/9961465. Licensed CC0.

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