Biology subjects

Taylor, G. C.

Publications and source records attributed to Taylor, G. C..

4 recordsLinked to original sources

bioRxiv2026

Divergent effects of target protein stabilisation versus overproduction on PROTAC activity

Protein degrader drugs such as PROTACs are being advanced as therapeutics targeted against oncogenic proteins. During tumorigenesis, oncogenic proteins can become constitutively activated via mechanisms including gene amplification, which increases protein production, and point mutations, which can extend protein half-life. Few experimental studies have addressed how disease-associated changes in target protein homeostasis influence PROTAC activity. We developed orthogonal methods to increase production or enhance stability of {beta}-catenin, an important oncoprotein and target for degrader therapeutics, and used the dTAG system to evaluate the consequences for PROTAC activity. Stabilising oncogenic missense mutations increased protein expression up to 5-fold but do not alter the PROTAC-imposed minimal steady-state level. In contrast, transcriptional upregulation increases both pre- and post-treatment target levels, revealing a synthesis-dependent ceiling on achievable depletion. Our results highlight distinct constraints on PROTAC activity arising from different mechanisms of oncogene activation, with potential implications for preclinical modelling, drug resistance and personalised medicine.

cancer biology↗

bioRxiv2025

Tissue-specific consequences of tag fusions on protein expression in transgenic mice

Genetic fusion of protein tags is widely used to study protein functions in vivo. It is well known that tag fusion can cause unwanted changes in protein stability, but whether this is an inherent property of the tagged protein, or can be influenced by the cell and tissue environment, is unclear. Using a series of genome edited mouse models, we show that tag-dependent changes in protein expression can vary across different primary cell and tissue contexts. In one case (Ncaph2), a C-terminal auxin-inducible degron fusion strongly increased protein stability in some tissues but decreased it in others. Destabilisation resulted from tissue-specific leakage of the auxin-inducible degron, which depended on TIR1 expression, and occurred selectively in the small intestine where basal concentrations of auxin / indole-3-acetic acid can reach levels that are sufficient to trigger protein degradation in cultured cells. Stabilisation occurred in post-mitotic cells via an endogenous degradation signal situated at the Ncaph2 C-terminus, which normally undergoes activation upon cell cycle exit, but is inactivated by C-terminal tag fusion. Our results highlight the underappreciated importance of cell and tissue environment in determining the consequences of tag fusions on protein expression, which may be particularly important in animal models that contain diverse cell types.

molecular biology↗

bioRxiv2020

A commercial antibody to the human condensin II subunit NCAPH2 cross-reacts with a SWI/SNF complex component

Condensin complexes compact and disentangle chromosomes in preparation for cell division. Commercially available antibodies raised against condensin subunits have been widely used to characterise their cellular interactome. Here we have assessed the specificity of a polyclonal antibody (Bethyl A302-276A) that is commonly used as a probe for NCAPH2, the kleisin subunit of condensin II, in mammalian cells. We find that, in addition to its intended target, this antibody cross-reacts with one or more components of the SWI/SNF family of chromatin remodelling complexes in an NCAPH2-independent manner. This cross-reactivity with an abundant chromatin-associated factor is likely to affect the interpretation of protein and chromatin immunoprecipitation experiments that make use of this antibody probe.

cell biology↗

bioRxiv2018

Heterochromatin delays CRISPR-Cas9 mutagenesis but does not influence repair outcome

CRISPR-Cas9 genome editing occurs in the context of chromatin, which is heterogeneous in structure and function across the genome. Chromatin heterogeneity is thought to affect genome editing efficiency, but this has been challenging to quantify due to the presence of confounding variables. Here, we develop a method that exploits the allele-specific chromatin status of imprinted genes in order to address this problem. Because maternal and paternal alleles of imprinted genes have identical DNA sequence and are situated in the same nucleus, allele-specific differences in the frequency and spectrum of Cas9-induced mutations can be attributed unequivocally to epigenetic mechanisms. We found that heterochromatin can impede mutagenesis, but to a degree that depends on other key experimental parameters. Mutagenesis was impeded by up to 7-fold when Cas9 exposure was brief and when intracellular Cas9 expression was low. Surprisingly, the outcome of mutagenic DNA repair was independent of chromatin state, with similar efficiencies of homology directed repair and deletion spectra on maternal and paternal chromosomes. Combined, our data show that heterochromatin imposes a permeable barrier that influences the kinetics, but not the endpoint of CRISPR-Cas9 genome editing, and suggest that therapeutic applications involving low-level Cas9 exposure will be particularly affected by chromatin status.

genetics↗