# Regulatory mechanisms for retinal ganglion cell genesis

> **NIH NIH R01** · STATE UNIVERSITY OF NEW YORK AT BUFFALO · 2024 · $459,457

## Abstract

Project Summary/Abstract
How individual retinal cell types arise from retinal progenitor cells (RPCs) is an active field of research, as it is
critical to understanding the generation of cellular diversity in the retina and developing therapeutic strategies
to treat degenerative retinal diseases. Many transcription factors involved in the generation of individual retinal
cell types have been identified. Single-cell technologies have led to unprecedented progress in discerning the
cellular relationships of the different lineage trajectories and the underlying changes in the epigenetic landscape.
The roles of individual transcription factors in shaping the epigenetic landscape to drive multipotent RPCs to
specific fates are also beginning to be revealed. A major finding from the single-cell RNA-seq studies is that all
the retinal lineages undergo a shared state, namely transitional RPCs (tRPCs), before fate determination. tRPCs
are multipotent and co-express genes involved in the different retinal cell types such as Atoh7 for RGCs and Otx2
and Neurod1 for photoreceptors. Our mapping of binding sites for Atoh7 and Otx2 by CUT&Tag suggests a
general paradigm via which the co-expressed transcription factors compete at enhancers of lineage-specific genes
to drive tRPCs to different cell fates. The focus of our lab has been on the mechanisms controlling RGC genesis.
In this application, we propose to address several key knowledge gaps regarding the emergence
of the RGC lineage from tRPCs. The first is the missing branch of upstream input as indicated by our scRNA-
seq analysis of the Atoh7-null retina. We hypothesize that the SoxC factors fulfill this role by function in parallel
with Atoh7 to promote RGC genesis based on previous findings on the roles of the SoxC factors in RGC genesis.
The second gap we aim to address is the molecular basis for the specificity of Atoh7 for the RGC lineage. This is
based on the fact that several proneural bHLH transcription factors, including Atoh7 and Neurod1, which all
bind to the E box motif, are co-expressed in tRPCs, but only Atoh7 promotes RGC formation. Using ectopic
expression in retinal explants, we have obtained compelling evidence which suggests that the RGC-specificity of
Atoh7 resides in the bHLH domain. We will further explore the molecular basis for the RGC specificity of Atoh7
in vivo using knockin mouse lines. Lastly, we will investigate the regulatory mechanisms leading to the fixation
of the RGC fate. We will leverage the candidate enhancers identified from our scATAC-seq and CUT&Tag
experiments for the key RGC specific transcription factor gene Pou4f2 and examine their contributions to the
eventual expression of Pou4f2. Our experiments are designed to address these gaps using a combined approach
of mouse genetics, immunohistochemistry, genomics, transcriptomics, and single cell techniques. These
proposed experiments aim to understand key gene regulatory events controlling the emergence of the RGC
li...

## Key facts

- **NIH application ID:** 10884289
- **Project number:** 5R01EY020545-12
- **Recipient organization:** STATE UNIVERSITY OF NEW YORK AT BUFFALO
- **Principal Investigator:** Xiuqian Mu
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $459,457
- **Award type:** 5
- **Project period:** 2011-03-01 → 2028-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10884289

## Citation

> US National Institutes of Health, RePORTER application 10884289, Regulatory mechanisms for retinal ganglion cell genesis (5R01EY020545-12). Retrieved via AI Analytics 2026-05-27 from https://api.ai-analytics.org/grant/nih/10884289. Licensed CC0.

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