Details

Autor(en) / Beteiligte

• Hebner, Yuki Christina

Titel

Investigating the Role of Transcription Factor ZFHX4 in Human Corticogenesis

Ort / Verlag

ProQuest Dissertations & Theses

Erscheinungsjahr

2024

Quelle

ProQuest Dissertations & Theses A&I

Beschreibungen/Notizen

• The human neocortex arises from the carefully orchestrated production and maturation of neurons and glia from neural progenitor pools during development. The molecular mechanisms underlying human corticogenesis are not well understood, but critically important to understanding our complex cognitive abilities and how the dysregulation of these mechanisms can lead to intellectual impairment and neuropsychiatric disease. The activity of cis gene-regulatory elements (GREs) and their corresponding transcription factors (TFs) play a pivotal role in modulating cell-specific transcriptional programs that drive corticogenesis.The emergence of genomic tools to profile gene expression and chromatin dynamics in single cells has facilitated the study of the interplay between gene regulatory elements and the TFs acting on these sites. Previously, our laboratory profiled transcriptional programs across developing neocortical cell types and identified several TFs enriched in neural progenitor cells located in the germinal zone (GZ) of the neocortex. In parallel, we profiled and contrasted chromatin dynamics between the GZ and the neuron-enriched cortical plate (CP), identifying GREs predicted to drive gene expression programs during neurogenesis.From these studies we identified a TF, ZFHX4, which is highly enriched in ventricular radial glia, and is the target of several GREs with enriched activity in the GZ. ZFHX4 has been implicated in several neurodevelopmental and intellectual disorders, including congenital bilateral isolated ptosis, syndromic Peters anomaly, and childhood apraxia of speech and has been reported to regulate cell differentiation at least in part through interactions with the chromatin remodeling complex NuRD.Despite its clinical relevance and enriched expression within neural progenitors of the developing brain, the role of ZFHX4 in neocortical development has never been studied. I hypothesize that ZFHX4 coordinates human cortical neurogenesis through the NuRD chromatin remodeling complex by modulating radial glia cell proliferation and differentiation, and that ZFHX4 loss-of-function-related dysregulation of corticogenesis underlies neurological disorders.Here, I detail the design, rationale, and outcomes of my efforts to identify the functional role and gene regulatory mechanisms of ZFHX4 in human neurogenesis using physiologically relevant neural stem cell models. In addition to characterizing a novel transcription factor, I have demonstrated the validity of using CRISPR-interference (CRISPRi) to functionally interrogate developmentally dynamic transcription factors like ZFHX4 and its putative GREs. Conducting CRISPRi experiments in complementary models of human corticogenesis have also contributed to developing an in vivo pipeline to study gene-regulatory functions and assess its role in lineage specification during cortical development. Altogether, these studies are expected to provide novel insights into mechanisms of human neocortical expansion and how their dysregulation leads to neurodevelopmental disorders.