Biology subjects

Goh, C. Y.

Publications and source records attributed to Goh, C. Y..

3 recordsLinked to original sources

bioRxiv2026

HOT1 functions as a homodimer to promote ALT-permissive chromatin

Telomere homeostasis is a tightly regulated and dynamic process sustained by a network of proteins that organize telomeric chromatin and safeguard chromosome stability. In ALT-positive cells, telomere maintenance relies on recombination-based mechanisms and is modulated by local chromatin states and epigenetic regulation. Here, we show that the telomeric binding protein HOT1 (HMBOX1) requires dimerization - depending both on interaction with the dimerization-mediators DYNLL1/2 and its intrinsic HNFp1 domain - for its stable association with telomeres in vivo. Loss of HOT1 leads to an epigenetic switch from H3K9acK14ac to H3K9me3 at telomeres accompanied by attenuated ALT activity as illustrated by reduced ALT recombination by-products (C-circles) and a decrease in telomere dysfunction-induced foci (TIFs). We further show via binding assays and cross-linking mass spectrometry (XL-MS) analyses that HOT1 directly interacts with telomeric nucleosomes, providing a molecular basis for its involvement in telomeric chromatin organization. Collectively, these findings suggest that HOT1 functions as a homodimer to promote a telomeric chromatin state that is highly permissive for ALT recombination.

cell biology↗

bioRxiv2025

The TARZN complex binds de novo enhancer mutations and promotes oncogenic expression in T-ALL

TAL1 is overexpressed in 40-60% of T-cell acute lymphoblastic leukemia (T-ALL) cases and forms an oncogenic core regulatory circuit (CRC) with other transcription factors such as LMO1, LMO2 and GATA3. In 5% of T-ALL cases an insertion of a consensus GT dinucleotide (MuTE) is observed upstream of the TAL1 gene, driving TAL1 overexpression. Using an in vitro reconstitution DNA pull-down assay combined with quantitative mass spectrometry, we identified proteins that preferentially bound to the MuTE sequence and demonstrated that among the candidates the RNA methyltransferase TARBP1 and the zinc finger proteins ZBTB2, ZBTB25 and ZNF639 form a complex that we term TARZN. Interestingly, the TARZN complex also bound to de novo super enhancer sites upstream of the LMO1 and LMO2 genes in T-ALL cells, indicating a putative common mechanism between these different non-coding driver mutations. Furthermore, knock-down of all TARZN members resulted in lower TAL1 protein expression in MuTE-positive but not in MuTE-negative T-ALL cells. Given TARZNs methyltransferase activity and the lack of concomitant TAL1 mRNA level changes, we investigated reduced TAL1 translation and identified reduced neo-synthesised TAL1 protein levels upon TARBP1 knockdown. Overall, these data suggest that the TARZN complex promotes oncogenic expression in T-ALL via co-transcriptional RNA methylation.

cell biology↗

bioRxiv2023

ChIP-MS reveals the local chromatin composition by label-free quantitative proteomics

Chromatin immunoprecipitation (ChIP) has been a cornerstone for epigenetic analyses over the last decades, but even coupled to sequencing approaches (ChIP-seq), it is ultimately limited to one protein at a time. In a complementary effort, we here combined ChIP with label-free quantitative (LFQ) mass spectrometry (ChIP-MS) to interrogate local chromatin compositions. We demonstrate the versatility of our approach at telomeres, with transcription factors, in tissue and by dCas9-driven locus-specific enrichment.

biochemistry↗