The minisatellite DNA Pc-1 consists of tandem repeats of d(GGCAG). We previously reported that a d(GGCAG)n strand folds into an intramolecular quadruplex under physiological conditions and that during replication the progression of DNA polymerase is blocked by the quadruplex in vitro. Therefore, the formation of the quadruplex was supposed to be responsible for the hypermutable features of Pc-1. Then, we have identified proteins that bind to Pc-1, one of which is hnRNP A1. Here, we have demonstrated that hnRNP A1 destroys the quadruplex of Pc-1 on binding and abrogates the arrest of DNA polymerase at the repeat. Thus, hnRNP A1 functions as if it is a chaperon to assist Pc-1 DNA to form the proper folding suitable for replication. We have also found that hnRNP A1 and a related protein, hnRNP D, destroy the quadruplex of telomere DNA, which suggests the involvement of these proteins in telomere maintenance as DNA chaperons.
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http://dx.doi.org/10.1093/nass/3.1.231 | DOI Listing |
Mol Biol Rep
January 2025
Department of Integrative Biology, School of Bio-Sciences and Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, 632014, India.
Telomerase, constituted by the dynamic duo of telomerase reverse transcriptase (TERT), the catalytic entity, and an integral RNA component (TERC), is predominantly suppressed in differentiated human cells due to postnatal transcriptional repression of the TERT gene. Dysregulation of telomerase significantly contributes to cancer development via telomere-dependent and independent mechanisms. Telomerase activity is often elevated in advanced cancers, with TERT reactivation and upregulation of TERC observed in early tumorigenesis.
View Article and Find Full Text PDFFront Biosci (Landmark Ed)
January 2025
The Key Laboratory of Model Animals and Stem Cell Biology in Hunan Province, Hunan Normal University Health Science Center, 410013 Changsha, Hunan, China.
Background: α thalassemia/mental retardation syndrome X-linked (ATRX) serves as a part of the sucrose nonfermenting 2 (SNF2) chromatin-remodeling complex. In interphase, ATRX localizes to pericentromeric heterochromatin, contributing to DNA double-strand break repair, DNA replication, and telomere maintenance. During mitosis, most ATRX proteins are removed from chromosomal arms, leaving a pool near the centromere region in mammalian cells, which is critical for accurate chromosome congression and sister chromatid cohesion protection.
View Article and Find Full Text PDFCancers (Basel)
January 2025
Department of Molecular Biosciences, University of South Florida, 4202 East Fowler Avenue, ISA2015, Tampa, FL 33620, USA.
Background/objectives: As cells divide, telomeres shorten through a phenomenon known as telomere attrition, which leads to unavoidable senescence of cells. Unprotected DNA exponentially increases the odds of mutations, which can evolve into premature aging disorders and tumorigenesis. There has been growing academic and clinical interest in exploring this duality and developing optimal therapeutic strategies to combat telomere attrition in aging and cellular immortality in cancer.
View Article and Find Full Text PDFCancers (Basel)
January 2025
Department of Medicine and Surgery, LUM University, Casamassima, 70010 Bari, Italy.
Background/objectives: Telomerase reverse transcriptase (TERT) is the catalytic subunit of the telomerase enzyme responsible for telomere length maintenance and is an important cancer hallmark. Our study aimed to clarify the mRNA expression of TERT in peritoneal mesothelioma (PeM), and to explore the relationship between its expression and the clinicopathological parameters and prognosis of patients with PeM.
Methods: In a cohort of 13 MpeM patients, we evaluated histotype, nuclear grade, mitotic count, necrosis, inflammation, Ki67, BAP1, MTAP and p16 expression by immunohistochemistry, / status by FISH and TERT mRNA expression by RNAscope.
Trials
January 2025
School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, B15 2TT, UK.
Background: Alzheimer's disease is caused by modifiable and non-modifiable risk factors. Randomised controlled trials have investigated whether the strongest genetic risk factor for Alzheimer's disease, APOE4, impacts the effectiveness of exercise on health. Systematic reviews are yet to evaluate the effect of exercise on physical and cognitive outcomes in APOE genotyped participants.
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