Biology subjects

Mayhew, C.

Publications and source records attributed to Mayhew, C..

3 recordsLinked to original sources

bioRxiv2022

Pioneer transcription factors coordinate active and repressive gene expression states to regulate cell fate

Pioneer transcription factors (TFs) regulate cell fate by establishing transcriptionally primed and active states. However, cell fate control requires the coordination of both lineage-specific gene activation and repression of alternative lineage programs, a process that is poorly understood. Here, we demonstrate that the pioneer TF Forkhead box A (FOXA), required for endoderm lineage commitment, coordinates with the PR domain zinc finger 1 (PRDM1) TF to recruit Polycomb repressive complexes, which establish bivalent enhancers and repress alternative lineage programs. Similarly, the pioneer TF OCT4 coordinates with PRDM14 to repress cell differentiation programs in pluripotent stem cells, suggesting this is a common feature of pioneer TFs. We propose that pioneer and PRDM TFs coordinate recruitment of Polycomb complexes to safeguard cell fate. One-Sentence SummaryPioneer and PRDM transcription factors repress alternative lineage programs.

cell biology↗

bioRxiv2021

High-throughput functional analysis of CFTR and other apically localized channels in iPSC derived intestinal organoids

Induced Pluripotent Stem Cells (iPSCs) can be differentiated into epithelial organoids that recapitulate the relevant context for CFTR and enable testing of therapies targeting Cystic Fibrosis (CF)-causing mutant proteins. However, to date, CF-iPSC-derived organoids have only been used to study pharmacological modulation of mutant CFTR channel activity and not the activity of other disease relevant membrane protein constituents. In the current work, we describe a high-throughput, fluorescence-based assay of CFTR channel activity in iPSC-derived intestinal organoids and describe how this method can be adapted to study other apical membrane proteins. In these proof-of-concept studies, we show how this fluorescence-based assay of apical membrane potential can be employed to study CFTR and ENaC channels and an electrogenic acid transporter in the same iPSC-derived intestinal tissue. This multiparameter phenotypic platform promises to expand CF therapy discovery to include strategies to target multiple determinants of epithelial fluid transport.

molecular biology↗

bioRxiv2017

A de novo missense mutation in TUBA1A results in reduced neural progenitor survival and differentiation

Mutations in tubulins have been implicated in numerous human neurobiological disorders collectively known as \"tubulinopathies.\" We identified a patient with severe cortical dysgenesis and a novel de novo heterozygous missense mutation in Tubulin Alpha 1a (TUBA1A, c.1225 G>T). Induced pluripotent stem cells derived from this individual were differentiated into two dimensional neural rosette clusters to identify underlying mechanisms for the severe cortical dysgenesis phenotype. Patient-derived clones showed evidence of impaired neural progenitor survival and differentiation with abnormal neural rosette formation, increases in cell death, and fewer post-mitotic neurons. These features correlate with the drastically underdeveloped cortical tissues seen in the proband. This is the first experimental evidence in human tissue suggesting a mechanism underlying the role for TUBA1A in cortical development.\n\nSUMMARY STATEMENTVariants in tubulin genes often lead to severe congenital brain malformations. Here we identify a new mutation in TUBA1A and use iPSCS to show this alters proliferation, differentiation and survival of neural progenitors.

genetics↗