# The Function of Small RNA-Based Viral Defense System in E. coli

> **NIH NIH R01** · RUTGERS, THE STATE UNIV OF N.J. · 2020 · $325,500

## Abstract

Almost all archaea and half of bacteria contain Clustered Regularly Interspaced
Short Palindromic Repeats-CRISPR-associated proteins (CRISPR-Cas) adaptive
immune systems that protect them against foreign genetic elements invasion. While
diverse, all CRISPR-Cas function through three common steps: (i) adaptation, i.e.,
acquisition of foreign DNA segments (spacers) into CRISPR arrays; (ii) CRISPR
array transcription and transcript processing to produce mature CRISPR RNAs
(crRNAs), and (iii) interference, when Cas effector enzymes are guided by crRNAs to
matching targets leading to target cleavage and ultimate invader genome
destruction. As any immune system, CRISPR-Cas must be capable of self/non-self
discrimination to prevent autoimmune death of the host caused by acquisition of
spacers from own DNA followed by self-interference. A
remarkable mechanism of
self/non-self discrimination called “priming” operates in type I CRISPR-Cas systems:
acquisition of spacers from DNA containing partial matches to pre-existing CRISPR
array spacers is dramatically stimulated compared to acquisition from DNA devoid of
such sequences. While partially matching crRNAs that promote primed adaptation
are incapable of efficient interference, all components of the interference machinery
are required for primed adaptation. The mechanistic relationship between the
interference and adaptation modules of CRISPR-Cas response during primed
adaptation is not clear. In this work, protein-nucleic acid complexes and nucleic acid
intermediates of CRISPR interference and primed adaptation by the Type I CRISPR-
Cas system of Escherichia coli, the best-studied microbe, will be characterized in
vivo and in vitro, and host functions that affect both processes will be revealed. In
addition to uncovering a functional link between CRISPR interference and primed
adaptation, programmable effector complexes with expanded targeting potential will
be created as a result of proposed work and highly sensitive quantitative biophysical
methods to study effector-target interactions will be developed.

## Key facts

- **NIH application ID:** 9858352
- **Project number:** 5R01GM104071-08
- **Recipient organization:** RUTGERS, THE STATE UNIV OF N.J.
- **Principal Investigator:** KONSTANTIN V SEVERINOV
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $325,500
- **Award type:** 5
- **Project period:** 2013-02-01 → 2021-01-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9858352

## Citation

> US National Institutes of Health, RePORTER application 9858352, The Function of Small RNA-Based Viral Defense System in E. coli (5R01GM104071-08). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9858352. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*