# Illuminating the gene regulation underlying meiotic differentiation

> **NIH NIH R35** · UNIVERSITY OF CALIFORNIA BERKELEY · 2020 · $238,968

## Abstract

ABSTRACT
 Meiosis is the conserved differentiation program that is responsible for gamete formation. As a cell
progress through meiotic differentiation, it undergoes unidirectional changes in cellular structure and function
that are largely driven by gene expression changes. Because the molecular basis for most meiotic transitions
remains mysterious, my lab aims to illuminate the gene regulatory circuitry that programs meiotic
differentiation. We use budding yeast to study this process because well studied meiotic factors are highly
conserved and because this organism uniquely offers access to the large number of highly synchronous cells
that is key to genomic approaches that we routinely employ. Our studies have enabled identification of proteins
involved in key meiotic processes, and new regulatory events during meiosis. These studies have also
uncovered major surprises in the genes that meiotic cells express and how they regulate these genes.
Among these surprises, we found an unconventional mode of gene regulation, involving regulated toggling
between a translatable mRNA isoform and one that is 5’ extended and poorly translated, to be commonly used
to drive meiotic protein levels over time. We have found this mode of regulation to be important in meiosis but
also in other conditions, and a major focus of our research is to better understand how it works. Although we
know that upstream open reading frames (uORFs) are responsible for repressed ORF translation on some
extended mRNA isoforms, we do not know why this is not true of all cases. We will address this question using
reporter experiments, and analysis of mRNA structures and sequences of repressed versus non-repressed
transcripts. We also do not understand how mRNA degradation impacts this regulation and meiotic gene
expression more broadly, which we will study using new metabolic labeling approaches.
 Beyond unconventional regulation of known genes, we also discovered that meiotic cells translate
many genes were not previously identified. These include hundreds of genes that are translated starting with
non-AUG codons, and thousands that are shorter than the 100 codon cutoff that was used to annotate
genomes. We have validated the expression of these non-canonical proteins and are now studying the
molecular mechanisms underlying their synthesis and their specific cellular roles. We are investigating why
non-AUG translation initiation is common in meiosis, primarily using study of candidate regulatory factors that
we have identified. We are performing pooled screens to identify roles for the many short meiotic proteins, and
directed study of cases in which the short proteins include domains of characterized proteins. Together the
projects proposed here will explain how and why meiotic cells employ non-canonical gene regulatory
features, which we believe is critical to unraveling the molecular control of meiotic progression.

## Key facts

- **NIH application ID:** 9851241
- **Project number:** 1R35GM134886-01
- **Recipient organization:** UNIVERSITY OF CALIFORNIA BERKELEY
- **Principal Investigator:** Gloria Ann Brar
- **Activity code:** R35 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $238,968
- **Award type:** 1
- **Project period:** 2020-01-01 → 2024-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9851241

## Citation

> US National Institutes of Health, RePORTER application 9851241, Illuminating the gene regulation underlying meiotic differentiation (1R35GM134886-01). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9851241. Licensed CC0.

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