Interventional, Multicenter, Open-label, Randomized, Non-comparative Trial Evaluating the Safety, in Terms of HBV Virological Control at 96 Weeks, of 2 Antiviral Treatment Relief Strategies, in Patients Co-infected With the HIV-1 and HBV Viruses

The main objective of this study is to evaluate at 96 weeks the safety with respect to hepatitis B control of 2 treatment reduction strategies for patients with previously controlled HIV-HBV co-infection on continuous triple therapy

开始日期2024-10-01

申办/合作机构

ANRS, Emerging Infectious Diseases

100 项与 DNA polymerase x RT 相关的临床结果

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100 项与 DNA polymerase x RT 相关的转化医学

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0 项与 DNA polymerase x RT 相关的专利（医药）

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176

项与 DNA polymerase x RT 相关的文献（医药）

2024-08-01·Journal of Biological Chemistry

Structural and biochemical characterization of cauliflower mosaic virus reverse transcriptase

Article

作者: Thangaraj, Vinuchakkaravarthy ; Prabaharan, Chandrasekaran ; Skowronek, Krzysztof ; Nowak, Elżbieta ; Nowotny, Marcin ; Chamera, Sebastian ; Figiel, Małgorzata ; Zajko, Weronika ; Szczepanowski, Roman H

Reverse transcriptases (RTs) are enzymes with DNA polymerase and RNase H activities. They convert ssRNA into dsDNA and are key enzymes for the replication of retroviruses and retroelements. Caulimoviridae is a major family of plant-infecting viruses. Caulimoviruses have a circular dsDNA genome that is replicated by reverse transcription, but in contrast to retroviruses, they lack integrase. Caulimoviruses are related to Ty3 retroelements. Ty3 RT has been extensively studied structurally and biochemically, but corresponding information for caulimoviral RTs is unavailable. In the present study, we report the first crystal structure of cauliflower mosaic virus (CaMV) RT in complex with a duplex made of RNA and DNA strands (RNA/DNA hybrid). CaMV RT forms a monomeric complex with the hybrid, unlike Ty3 RT, which does so as a dimer. Results of the RNA-dependent DNA polymerase and DNA-dependent DNA polymerase activity assays showed that individual CaMV RT molecules are able to perform full polymerase functions. However, our analyses showed that an additional CaMV RT molecule needs to transiently associate with a polymerase-competent RT molecule to execute RNase H cuts of the RNA strand. Collectively, our results provide details into the structure and function of CaMV RT and describe how the enzyme compares to other related RTs.

2024-01-01·DNA Repair

Somatic mutation patterns at Ig and Non-Ig Loci

Article

作者: Steele, Edward J ; Lindley, Robyn A ; Franklin, Andrew

The reverse transcriptase (RT) model of immunoglobulin (Ig) somatic hypermutation (SHM) has received insufficient scientific attention. This is understandable given that DNA deamination mediated by activation-induced deaminase (AID), the initiating step of Ig SHM, has dominated experiments since 2002. We summarise some key history of the RT Ig SHM model dating to 1987. For example, it is now established that DNA polymerase η, the sole DNA repair polymerase involved in post-replication short-patch repair, is an efficient cellular RT. This implies that it is potentially able to initiate target site reverse transcription by RNA-directed DNA repair at AID-induced lesions. Recently, DNA polymerase θ has also been shown to be an efficient cellular RT. Since DNA polymerase θ plays no significant role in Ig SHM, it could serve a similar RNA-dependent DNA polymerase role as DNA polymerase η at non-Ig loci in the putative RNA-templated nucleotide excision repair of bulky adducts and other mutagenic lesions on the transcribed strand. A major yet still poorly recognised consequence of the proposed RT process in Ig SHM is the generation of significant and characteristic strand-biased mutation signatures at both deoxyadenosine/deoxythymidine and deoxyguanosine/deoxycytidine base pairs. In this historical perspective, we highlight how diagnostic strand-biased mutation signatures are detected in vivo during SHM at both Ig loci in germinal centre B lymphocytes and non-Ig loci in cancer genomes. These strand-biased signatures have been significantly obscured by technical issues created by improper use of the polymerase chain reaction technique. A heightened awareness of this fact should contribute to better data interpretation and somatic mutation pattern recognition both at Ig and non-Ig loci.

2023-03-01·Journal of Biological Chemistry

Human DNA polymerase η promotes RNA-templated error-free repair of DNA double-strand breaks

Article

作者: Hazra, Tapas ; Mitra, Joy ; Hegde, Muralidhar L ; Sarker, Altaf H ; Islam, Azharul ; Tapryal, Nisha ; Chakraborty, Anirban ; Manohar, Kodavati

A growing body of evidence indicates that RNA plays a critical role in orchestrating DNA double-strand break repair (DSBR). Recently, we showed that homologous nascent RNA can be used as a template for error-free repair of double-strand breaks (DSBs) in the transcribed genome and to restore the missing sequence at the break site via the transcription-coupled classical nonhomologous end-joining (TC-NHEJ) pathway. TC-NHEJ is a complex multistep process in which a reverse transcriptase (RT) is essential for synthesizing the DNA strand from template RNA. However, the identity of the RT involved in the TC-NHEJ pathway remained unknown. Here, we report that DNA polymerase eta (Pol η), known to possess RT activity, plays a critical role in TC-NHEJ. We found that Pol η forms a multiprotein complex with RNAP II and other TC-NHEJ factors, while also associating with nascent RNA. Moreover, purified Pol η, along with DSBR proteins PNKP, XRCC4, and Ligase IV can fully repair RNA templated 3'-phosphate-containing gapped DNA substrate. In addition, we demonstrate here that Pol η deficiency leads to accumulation of R-loops and persistent strand breaks in the transcribed genes. Finally, we determined that, in Pol η depleted but not in control cells, TC-NHEJ-mediated repair was severely abrogated when a reporter plasmid containing a DSB with several nucleotide deletion within the E. coli lacZ gene was introduced for repair in lacZ-expressing mammalian cells. Thus, our data strongly suggest that RT activity of Pol η is required in error-free DSBR.