Exploring genotype-phenotype correlations in Sox10 mutations

Project description:
What genetic variants cause what phenotypic changes? The SOX proteins form a family of transcription factors with key
functions in embryonic development and cellular homeostasis, with these functions highly conserved across the
vertebrates. Due to their complex roles in multiple cell-types, SOX mutant phenotypes are often diverse, even for a single
gene. Whilst much is known of their protein structure and DNA binding characteristics, we are still ignorant of the
relationship between their structure and their cellular functions, with the genotype-phenotype correlation remaining
obscure even in well-studied examples, such as SOX10 (Pingault et al., 2022, J. Med. Genet. 59, 105-114). SOX10 is
expressed widely in the neural crest, an embryonic population of highly multipotent progenitors, and SOX10 mutations
may result in pigment, hearing, olfactory and neural phenotypes, individually or in various combinations. The variation in
phenotypes may reflect subtle impacts of the mutations (e.g. gain of function), or other factors (e.g. presence of modifier
loci). We have shown the conserved role for Sox10 in zebrafish and mammals (e.g. Kelsh, 2006, Bioessays 28, 788-798).
Furthermore, in the course of a current DTP studentship supervised by same team, we have established a method for
generating CRISPR/Cas9-induced precise genomic modifications, using chemical modulation to enhance Homology-
Directed Repair (Zhang et al., 2018, J. Biol. Chem. 293, 6611-6622; Aksoy et al., 2019, Communications Biology, 2, 198).
This, combined with the ready accessibility and phenotypic characterisation of zebrafish embryos (e.g. Alhashem et al.,
2022, eLife 11:e73550; Camargo-Sosa et al., 2019, PLoS Genetics 15, e1007941), makes the zebrafish an ideal system to
explore the precise impacts of specific mutational changes in a relatively constrained genetic background.
To assess the genotype-phenotype discrepancy, the successful applicant will create an extensive series of zebrafish
sox10 alleles, selected from amongst the human variants linked to disease phenotypes; mutations will be maintained as
heterozygotes, since most are likely to be homozygous lethal. Dominant and recessive phenotypes will then be
characterised quantitatively for all the pigment and neural cell-types. This will enable us to disentangle the currently
obscure, but fundamental, structure-function relationships for this vital developmental regulatory factor.
This interdisciplinary project will give an opportunity to develop numerous specific skillsets, including in zebrafish genetics
and husbandry, phenotypic analysis including by in situ hybridisation and immunofluorescence, confocal and light
sheet microscopy, molecular biology, and bioinformatics. In addition, the student will benefit from collaborative
interaction with mouse and human geneticists at the Institut Imagine (Paris)