Biology subjects

Connelly, C. J.

Publications and source records attributed to Connelly, C. J..

3 recordsLinked to original sources

bioRxiv2023

Validation of human telomere length trans-ancestry meta-analysis association signals identifies POP5 and KBTBD6 as novel human telomere length regulation genes

Telomere length genome-wide association studies (GWAS) have become well-powered to detect novel genes in telomere length regulation. However, no prior work has validated these putative novel genes to confirm the contribution of GWAS loci to telomere length regulation. We conducted a trans-ancestry meta-analysis of 211,369 individuals. Through enrichment analyses of chromatin state and cell-type heritability we identified blood and immune cells as the most relevant cell type to examine telomere length association signals. We validated specific GWAS associations by overexpressing KBTBD6, a component of an E3 ubiquitin ligase complex, and POP5, a component of the Ribonuclease P/MRP complex, and demonstrating that both lengthened telomeres as predicted by our statistical analyses. CRISPR/Cas9 deletion of the predicted causal regions of these association peaks in K562 immortalized blood cells reduced expression of these genes, demonstrating that these loci are related to transcriptional regulation of KBTBD6 and POP5, respectively. Together our results demonstrate the utility of telomere length GWAS in the identification of novel telomere length regulation mechanisms and highlight the importance of the proteasome-ubiquitin pathway in telomere length regulation.

genetics↗

bioRxiv2019

Tel1 activation by the MRX complex is sufficient for telomere length regulation but not for the DNA damage response in S. cerevisiae

Previous models suggested that regulation of telomere length in S. cerevisiae by Tel1(ATM) and Mec1(ATR) parallel the established pathways regulating the DNA damage response. Here we provide evidence that telomere length regulation differs from the DNA damage response in both the Tel1 and Mec1 pathways. We found that Rad53 mediates a Mec1 telomere length regulation pathway but is dispensable for Tel1 telomere length regulation, whereas in the DNA damage response Rad53 is regulated by both Mec1 and Tel1. Using epistasis analysis with a Tel1 hypermorphic allele, Tel1-hy909, we found that the MRX complex is not required downstream of Tel1 for telomere elongation but is required downstream of Tel1 for the DNA damage response. Since models that invoke a required end processing event for telomerase elongation are primarily based on the yeast pathways, our data call for a re-examination of the requirement for telomere end processing in both yeast and mammalian cells.

molecular biology↗

bioRxiv2018

TIN2 functions with TPP1/POT1 to stimulate telomerase processivity

Telomere length maintenance is crucial for cells that divide many times. TIN2 is an important regulator of telomere length, and mutations in TINF2, the gene encoding TIN2, cause short telomere syndromes. While the genetics underscore the importance of TIN2, the mechanism through which TIN2 regulates telomere length remains unclear. Here, we characterize the effects of TIN2 on telomerase activity. We identified a new isoform in human cells, TIN2M, that is expressed at similar levels to previously studied TIN2 isoforms. Additionally, we found that all three TIN2 isoforms stimulated telomerase processivity beyond the previously characterized stimulation by TPP1/POT1. Mutations in the TPP1 TEL-patch abrogated this stimulation, implicating TIN2 as a component of the TPP1/POT1 processivity complex. All three TIN2 isoforms localized to telomeres in vivo but had distinct effects on telomere length, suggesting they are functionally distinct. These data contrast previous descriptions of TIN2 a simple scaffolding protein, showing that TIN2 isoforms directly regulate telomerase.

molecular biology↗