# Regulation of DNA Replication Timing by Origin Recognition Complex (ORC) Phosphorylation

> **NIH NIH F31** · VANDERBILT UNIVERSITY · 2022 · $30,362

## Abstract

PROJECT SUMMARY
Successful duplication of the genome requires the accurate replication of billions of bases. Failure to do so
results in genomic instability and ultimately a host of diseases. To mitigate against this, DNA replication is a
coordinated and tightly regulated process; however, this regulation must also be flexible as DNA replication is
subject to change through development and differentiation. Much still remains unknown regarding exactly how
DNA replication is regulated and how this regulation changes through development. One such regulatory process
where much remains to be discovered is the replication timing program, which controls when certain segments
of the genome are replicated during S phase. Replication timing (RT) is a highly conserved phenomenon, found
in species ranging from yeast to humans, yet the precise mechanisms that govern replication timing remains
unknown. RT has also been implicated in mutation rates and the development of drug resistance in certain
cancers. Rif1, a conserved active regulator of RT provides a key to unlock the underlying molecular mechanisms
controlling RT. Rif1 is thought to delay the activation of replicative helicases that lie within certain sections of the
genome, causing these sections to replicate later in S phase. How Rif1 is targeted to these genomic regions to
cause delayed replication remains unclear. We sought to determine how Rif1 controls RT by carrying out
immunoprecipitations of Rif1 followed by high-resolution mass spectrometry. We discovered that Rif1 co-
immunoprecipated with the origin recognition complex (ORC). ORC is the first complex to bind to DNA during
the initiation of DNA replication and controls where across the genome DNA replication will start. In this proposal,
we seek to characterize the interaction between Rif1 and ORC. To achieve this, we will determine the molecular
relevance of this interaction, characterize where Rif1 and ORC bind to the genome through the cell cycle, and
use in vitro approaches to determine if the Rif1/ORC interaction is direct. The findings from this work could
provide a new mechanism paradigm for how Rif1 controls RT, which will likely be applicable to other species as
Rif1 and ORC are functionally conserved. This work will also provide insight into the regulation driving replication
timing and DNA replication, both of which critical for maintaining genomic stability and integrity. Furthermore,
this proposal will provide the opportunity to learn bioinformatic and biochemical skills widely applicable to careers
in science, enhance critical thinking and problem-solving skills, and improve scientific communication skills by
formally presenting this work and national conferences and university meetings. I will work with my mentors and
the ASPIRE program through the office of career development office at Vanderbilt to identify career development
opportunities. Lastly, I will continue to develop mentorship skills by training undergraduates at Van...

## Key facts

- **NIH application ID:** 10378513
- **Project number:** 5F31GM142286-02
- **Recipient organization:** VANDERBILT UNIVERSITY
- **Principal Investigator:** Logan R Richards
- **Activity code:** F31 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $30,362
- **Award type:** 5
- **Project period:** 2021-04-01 → 2023-03-17

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10378513

## Citation

> US National Institutes of Health, RePORTER application 10378513, Regulation of DNA Replication Timing by Origin Recognition Complex (ORC) Phosphorylation (5F31GM142286-02). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10378513. Licensed CC0.

---

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