Search

* Context.--Quantification and detection of the t(9;22) (BCR-ABL1) translocation in chronic myelogenous leukemia and B-lymphoblastic leukemia are important for directing treatment protocols and monitoring disease relapse. However, quantification using traditional reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) is dependent on a calibration curve and is prone to laboratory-to-laboratory variation. Droplet digital polymerase chain reaction (ddPCR) is a novel method that allows for highly sensitive absolute quantification of transcript copy number. As such, ddPCR is a good candidate for disease monitoring, an assay requiring reproducible measurements with high specificity and sensitivity. Objective.--To compare results of ddPCR and RT-qPCR BCR-ABL1 fusion transcript measurements of patient samples and determine if either method is superior. Design.--We optimized and standardized a 1-step multiplexed ddPCR assay to detect BCR-ABL1 p190 and ABL1 e10 transcripts. The ddPCR optimization included varying cycle number and primer concentration with standardization of droplet generation and droplet number and analyses to improve data sensitivity. Following optimization, ddPCR measurements were performed on clinical samples and compared with traditional RT-qPCR results. Results.--Droplet digital polymerase chain reaction was able to detect the BCR-ABL1 p190 transcript to 0.001% (1:10 5) with a calculated limit of detection and limit of quantitation of 4.1 and 5.3 transcripts, respectively. When tested on patient samples, ddPCR was able to identify 20% more positives than a laboratory-developed 2-step RT-qPCR assay. Conclusions.--Droplet digital polymerase chain reaction demonstrated increased detection of BCR-ABL1 compared with RT-qPCR. Improved detection of BCRABL1 p190 and the potential for improved standardization across multiple laboratories makes ddPCR a suitable method for disease monitoring in patients with acute B-lymphoblastic leukemia., Droplet digital polymerase chain reaction (ddPCR) is a novel polymerase chain reaction (PCR) technique reliant on massive sample partitioning to generate individual reaction chambers (droplets) in which individual amplification targets [...]

Introduction: The clinical relevance of low-level viraemia (LLV) and virological outcomes among children living with HIV (CLHIV) remains controversial. This study aimed to determine the impact of LLV on virological failure (VF) among Asian CLHIV on first-line combination antiretroviral therapy (cART). Methods: CLHIV aged 14 days, or received treatment and care at sites with a pVL lower limit of detection >50 copies/mL were excluded. LLV was defined as a pVL 50 to 1000 copies/mL, and VF as a single pVL >1000 copies/mL. Baseline was the time of the second pVL < 50 copies/mL. Cox proportional hazards models were performed to assess the association between LLV and VF. Results: From January 2008 to September 2016, 508 CLHIV (55% female) were eligible for the study. At baseline, the median age was 9.6 (IQR: 7.0 to 12.3) years, cART duration was 1.4 (IQR: 1.3 to 1.8) years, 97% of CLHIV were on non-nucleoside reverse transcriptase inhibitor-based regimens, and the median CD4 was 25% (IQR: 20% to 30%). Over a median follow-up time of 6.0 (IQR: 3.1 to 8.9) years from baseline, 86 CLHIV (17%) had ever experienced LLV, of whom 32 (37%) had multiple LLV episodes. Female sex, living in Malaysia (compared to Cambodia), having family members other than biological parents/grandparents as a primary caregiver, and baseline CD4 < 25% increased risk of LLV. Overall, 115 children (23%) developed VF, corresponding to a rate of 4.0 (95%CI: 3.4 to 4.9) per 100 person-years of follow-up (PYFU). VF was greater among children who had ever experienced LLV compared with those who maintained virological suppression throughout the study period (8.9 vs. 3.3 per 100 PYFU; p < 0.001). In multivariable analyses, ever experiencing LLV was associated with increased risk of subsequent VF (adjusted hazard ratio: 3.01; 95%CI: 1.97 to 4.60). Conclusions: LLV increased the risk of subsequent VF among Asian CLHIV who had previously been suppressed on first-line cART. Adherence interventions and additional targeted pVL monitoring may be warranted among children with LLV to facilitate early detection of VF. Keywords: viraemia; viral blip; viral rebound; paediatric; treatment failure; Asia, 1 | INTRODUCTION HIV plasma viral load (pVL) is an important tool to monitor treatment response and assess medication adherence in people living with HIV. One of the primary aims [...]

Introduction: To date, very little programmatic data has been published regarding serial antiretroviral (ARV) levels in infants exposed to maternal treatment and/or infant prophylaxis during the first months of life. Such data provide the opportunity to describe the proportion of infants exposed to virologically suppressive levels of ARVs and to gauge adherence to the prevention of mother-to-child transmission of HIV (PMTCT) programme. Methods: From August 2014 to January 2016, HIV-exposed infants born at Kalafong Provincial Tertiary Hospital in Pretoria, South Africa were enrolled as part of an observational cohort study. Plasma samples from HIV-exposed uninfected infants were obtained at birth, 6-weeks, 10-weeks and 14-weeks of age and quantitative efavirenz (EFV) and nevirapine (NVP) drug eve testing performed using liquid chromatography-mass spectrometry, irrespective of maternal ARV regimen. Descriptive analysis of EFV and NVP levels in relation to self-reported maternal and infant ARV exposure was performed. EFV levels >500 ng/mL and NVP levels >100 ng/mL were reported based on studies suggesting that trough levels above these thresholds are associated with virological suppression and PMTCT respectively. Results: Among 66 infants exposed to maternal EFV in utero, 29 (44%) had virologically suppressive plasma EFV levels at birth, with a median level of 1665 ng/mL (IQR: 1094 to 3673). Among infants who were exclusively breastfed at 6-, 10- and 14 weeks, 13/48 (27%), 5/25 (25%) and 0/21 (0%) had virologically suppressive EFV levels. Among 64 infants whose mothers reported administering daily infant NVP at time of their 6-week HIV PCR test, only 45 (70%) had NVP levels above the minimum prophylactic trough level. Conclusions: During the first 10-weeks after delivery, a quarter of breastfed infants born to women on an EFV-containing treatment regimen maintained virologically suppressive EFV plasma levels. This finding highlights the importance of both careful monitoring of ARV side effects and repeat HIV PCR after the first few months of life among HIV-exposed uninfected infants. As 30% of infants had inadequate NVP plasma levels at 6-weeks of age, adherence counselling to caregivers regarding infant prophylaxis needs to be enhanced to further reduce mother-to-child transmission of HIV. Keywords: PMTCT; option B+; antiretrovirals; efavirenz; nevirapine; toxicity; adherence; early infant diagnosis, 1 INTRODUCTION As combination antiretroviral therapy (cART) becomes more readily available in resource-limited settings, a rapid rise in the number of foetal antiretroviral (ARV) drug exposures is expected [1]. Current [...]

Introduction: Recommendations on the optimal frequency of plasma viral load (pVL) monitoring in children living with HIV (CLWH) who are stable on combination antiretroviral therapy (cART) are inconsistent. This study aimed to determine the impact of annual versus semi-annual pVL monitoring on treatment outcomes in Asian CLWH. Methods: Data on children with perinatally acquired HIV aged 1.5 tests/patient/year. Treatment failure was defined as virologic failure (two consecutive pVL >1000 copies/mL), change of antiretroviral drug class, or death. Baseline was the date of the second consecutive pVL Results: During January 2008 to March 2015, there were 1220 eligible children from 10 sites that performed at least annua pVL monitoring, 1042 (85%) and 178 (15%) were from sites performing annual (n = 6) and semi-annual pVL monitoring (n = 4) respectively. Pre-cART, 675 children (55%) had World Health Organization clinical stage 3 or 4, the median nadir CD4 percentage was 9%, and the median pVL was 5.2 [log.sub.10] copies/mL. At baseline, the median age was 9.2 years, 64% were on nevirapine-based regimens, the median cART duration was 1.6 years, and the median CD4 percentage was 26%. Over the follow-up period, 258 (25%) CLWH with annual and 40 (23%) with semi-annual pVL monitoring developed treatment failure, corresponding to incidence rates of 5.4 (95% CI: 4.8 to 6.1) and 4.3 (95% CI: 3.1 to 5.8) per 100 patient-years of follow-up respectively (p = 0.27). In multivariable analyses, the frequency of pVL monitoring was not associated with treatment failure (adjusted hazard ratio: 1.12; 95% CI: 0.80 to 1.59). Conclusions: Annual compared to semi-annual pVL monitoring was not associated with an increased risk of treatment failure in our cohort of virally suppressed children with perinatally acquired HIV on first-line NNRTI-based cART. Keywords: antiretroviral treatment; viral load; monitoring; paediatric; treatment failure; Asia, 1 INTRODUCTION In 2017, there were an estimated 1.8 million children younger than 15 years of age living with HIV (CLWH) worldwide, of whom 110,000 were in the Asia-Pacific region [...]

Appropriate repair of DNA lesions and the inhibition of DNA repair activities at telomeres are crucial to prevent genomic instability. By fuelling the generation of genetic alterations and by compromising cell viability, genomic instability is a driving force in cancer and ageing (1,2).Herewe identifyM AD2L2(also known asMAD2B or REV7) through functional genetic screening as a novel factor controlling DNA repair activities at mammalian telomeres. We show that MAD2L2 accumulates at uncapped telomeres and promotes non-homologous end-joining (NHEJ)-mediated fusion of deprotected chromosome ends and genomic instability. MAD2L2 depletion causes elongated 3' telomeric overhangs, indicating that MAD2L2 inhibits 5' end resection. End resection blocks NHEJ while committing to homology-directed repair, and is under the control of 53BP1, RIF1 and PTIP (3). Consistent with MAD2L2 promoting NHEJ-mediated telomere fusion by inhibiting 5' end resection, knockdown of the nucleases CTIP or EXO1 partially restores telomere-driven genomic instability in MAD2L2-depleted cells. Control of DNA repair by MAD2L2 is not limited to telomeres. MAD2L2 also accumulates and inhibits end resection at irradiation-induced DNA double-strand breaks and promotes end-joining of DNA double-strand breaks in several settings, including during immunoglobulin class switch recombination. These activities of MAD2L2 depend on ATM kinase activity, RNF8, RNF168,53BP1 and RIF1, but not on PTIP, REV1 and REV3, the latter two acting with MAD2L2 in translesion synthesis (4). Together, our data establish MAD2L2 as a crucial contributor to the control of DNA repair activity by 53BP1 that promotes NHEJ by inhibiting 5' end resection downstream of RIF1., As the processes underlying telomere-driven genomic instability are not completely understood, we performed a functional genetic screen to identify telomere-induced genomic instability regulators (TIGIRs). The TIGIR screen relies on well-controlled [...]

Purpose Zymosan-induced generalized inflammation is the only experimental model that reproduces characteristics of human multiple organ dysfunction syndrome (MODS). Toll-like receptors (TLRs) are key components in innate immune responses and their signaling pathway is known to activate target genes such as nuclear factor-[kappa]B (NF-[kappa]B) and cytokines that are involved in inflammation and immune responses. We previously reported that hyperbaric oxygen (HBO) therapy is effective in the treatment of severe zymosan-induced inflammation in MODS. The aim of this study was to investigate the effect of HBO exposure on TLR2 and TLR4 signal transduction and organ dysfunction during MODS induced by zymosan in the rat. Methods Male Wistar rats were randomized into four groups and treated as follows: (1) saline solution (control); (2) zymosan; (3) HBO 4 and 11 h after zymosan injection; (4) HBO 4 and 11 h after saline solution injection. Zymosan-induced damage of the lungs, liver, and small intestine was evaluated using histology and biochemistry. The activation of the TLR signaling pathway was measured with Western blot, reverse transcriptase polymerase chain reaction analysis (RT-PCR), and immunohistochemistry. Results Zymosan induced a severe inflammatory response characterized by the activation of the TLR signaling pathway and by an organ dysfunction. HBO exposure significantly reduced the development of lung, liver, and intestine injury in our experimental model. It also significantly reduced the zymosan-induced expression of TLR2 and TLR4, NF-[kappa]B activation, and cytokine production. Conclusions Taken together, these results suggest that, by interfering with the TLR pathway, HBO treatment may exert a protective effect against tissue injury caused by zymosan-induced generalized inflammation., Author(s): Barbara Rinaldi [sup.1], Salvatore Cuzzocrea [sup.2], Maria Donniacuo [sup.1], Annalisa Capuano [sup.1], Donatella Di Palma [sup.1], Francesco Imperatore [sup.1], Emanuela Mazzon [sup.2], Rosanna Di Paola [sup.2], Loredana Sodano [sup.1], [...]

Objective To assess 12-month survival, pharmacokinetics, immunologic and virologic efficacy, tolerance, compliance and drug resistance in HIV-infected children in Bobo-Dioulasso, Burkina Faso, receiving once-daily highly-active antiretroviral therapy as a combination of didanosine (DDI), lamivudine (3TC) and efavirenz (EFV). Methods In the ANRS 12103 open phase II trial, HIV-infected children were examined at inclusion and monthly thereafter. CD4+ T-lymphocyte (CD4) count, plasma concentration of ribonucleic acid (RNA) of human immunodeficiency virus type 1 (HIM-1) and haematologic and biochemical parameters were measured at baseline and every trimester. HIV-1 resistance testing was performed in case of viral escape. Drug plasma concentrations were determined with high-performance liquid chromatography. Findings From February 2006 to November 2007, 51 children (39% girls) with a mean age of 6.8 years were enrolled and treated for 12 months. At baseline, Z scores for mean weight-for-age and mean height-for-age were -2.01 and -2.12, respectively. Mean CD4% was 9.0. Median plasma HIV-1 RNA viral load was 5.51 [log.sub.10] copies per millilitre (cp/ml). Two children (3.9%) died and another 11 (22%) suffered 13 severe clinical events. At month 12, mean WAZ had improved by 0.63 (P< 0.001) and mean HAZ by 0.57 (P< 0.001). Mean CD4% had risen to 24 (P< 0.001). Viral load was below 300 RNA cp/ml in 81% of the children; HIV resistance mutations were detected in 11 (21.6%). Conclusion The once-a-day combination of DDI + 3TC + EFV is an alternative first-line treatment for HIV-1-infected children. Dose adjustment should further improve efficacy. Objectif Evaluer sur 12 mois la survie, la pharmacocinetique, l'efficacite immunologique et virologique, la tolerance, l'observance et la resistance au medicament chez des enfants infectes par le VlH a Bobo-Dioulasso, Burkina Faso, et qui recoivent une fois par jour une therapie antiretrovirale hautement active par une association de didanosine (DDI), de lamivudine (3TC) et d'efavirenz (EFV). Methodes Dans l'essai ouvert ANRS 12103 phase II, des enfants infectes par le VlH ont ete examines au moment de l'inclusion et ensuite chaque mois. Le taux de lymphocytes T CD4 (CD4), la concentration plasmatique d'acide ribonucleique (ARN) du virus de l'immunodeficience humaine type 1 (VlH-1), ainsi que des parametres hematologiques et biochimiques ont ete mesures au debut de l'etude et chaque trimesb'e. Le test de resistance au VIH-1 a ete effectue dans les cas d'evasion virale. Les concentrations plasmatiques de medicament ont ete determinees par chromatographie liquide a haute performance. Resultats De fevrier 2006 a novembre 2007, 51 enfants (39% de filles), avec une moyenne d'age de 6,8 ans, ont ete selectionnes et traites pendant 12 mois. Au debut de l'etude, les ecarts reduits pour le poids moyen par age et la taille moyenne par age etaient respectivement de -2,01 et -2,12. Le CD4 moyen etait 9,0%. La charge virale plasmatique mediane de I'ANR VIH-1 etait de 5,51 legue copies par millilitre (cp/ ml). Deux enfants (3,9%) sont decedes et 11 autres (22%) ont souffert 13 evenements cliniques severes. Au 12e mois, le WAZ moyen s'etait ameliore de 0,63 (P Conclusion L'association DDI + 3TC + EFV en une prise quotidienne est un traitement alternatif de premiere intention pour les enfants infectes au VIH-1. L'adaptation de la dose devrait encore ameliorer l'efficacite. Objetivo Evaluar a 12 meses la supervivencia, la farmacocinetica, la eficacia inmunologica y virologica, la tolerancia, el cumplimiento terapeutico y la resistencia a los medicamentos en ninos infectados con el VIH en Bobo-Dioulasso (Burkina Faso), que reciben una vez al dia un tratamiento antirretrovirico muy activo, constituido por la asociacion de didanosina (DDI), lamivudina (3TC) y efavirenz (EFV). Metodos En el ensayo clinico ANRS 12103, abierto y de fase II, se examino a los ninos infectados con el VIH en el momento de la inclusion y, a continuacion, mensualmente. Se midieron el recuento de linfocitos T [CD4.sup.+] (CD4), la concentracion plasmatica de acido ribonucleico (ARN) del virus de la inmunodeficiencia humana de tipo 1 (VlH-1) y los parametros hematologicos y bioquimicos, al inicio y cada trimestre. Las pruebas de resistencia al VIH-1 se realizaron en el caso de escape virico. Las concentraciones plasmaticas del farmaco se determinaron con cromatografia en fase liquida de alta resolucion. Resultados Desde febrero del 2006 a noviembre del 2007, 51 ninos (39% ninas) con una edad media de 6,8 anos fueron registrados y tratados durante 12 meses. Al inicio del estudio, las puntuaciones Z del peso medio por edad y la altura media por edad fueron -2,01 y -2,12 respectivamente. El % medio de CD4 fue 9,0. La carga virica media de RNA del HIV-1 en plasma fue de 5,51 [log.sub.10] copias por mililitro (cp/ml). Dos ninos (3,9%) murieron y otros 11 (22%) sufrieron 13 acontecimientos clinicos graves. En el mes 12, el WAZ medio (peso por edad segun la puntuacion Z) habia mejorado en un 0,63 (p < 0,001) y el HAZ medio (altura por edad segun la puntuacion Z) en 0,57 (p < 0,001). El % medio de CD4 habia subido a 24 (p < 0,001). La carga virica estaba por debajo de 300 ARN cp/ml en el 81% de los ninos; se detectaron mutaciones de resistencia al VlH en 11 (21,6%). Conclusion La asociacion de DDI + 3TC + EFV una vez al dia es un tratamiento alternativo de primera linea para los ninos infectados con el VIH-1. Un ajuste de la dosis deberia mejorar todavia mas la eficacia., Introduction Worldwide, over two million children are infected by human immunodeficiency virus type l (HIV-1). (1) Ninety per cent of them live in Africa, and only 38% of those who [...]

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.cell.2006.07.027 Byline: Scott Bailey (1)(3), Richard A. Wing (1), Thomas A. Steitz (1)(2)(3) Abstract: The crystal structure of Thermus aquaticus DNA polymerase III [alpha] subunit reveals that the structure of the catalytic domain of the eubacterial replicative polymerase is unrelated to that of the eukaryotic replicative polymerase but rather belongs to the Pol[beta]-like nucleotidyltransferase superfamily. A model of the polymerase complexed with both DNA and [beta]-sliding clamp interacting with a reoriented binding domain and internal [beta] binding site was constructed that is consistent with existing biochemical data. Within the crystal, two C-terminal domains are interacting through a surface that is larger than many dimer interfaces. Since replicative polymerases of eubacteria and eukaryotes/archaea are not homologous, the nature of the replicative polymerase in the last common ancestor is unknown. Although other possibilities have been proposed, the plausibility of a ribozyme DNA polymerase should be considered. Author Affiliation: (1) Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA (2) Department of Chemistry, Yale University, New Haven, CT 06520, USA (3) Howard Hughes Medical Institute, Yale University, New Haven, CT 06520, USA Article History: Received 16 May 2006; Revised 5 July 2006; Accepted 20 July 2006 Article Note: (miscellaneous) Published: September 7, 2006

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.cell.2006.07.028 Byline: Meindert H. Lamers (1), Roxana E. Georgescu (3), Sang-Gyu Lee (3), Mike O'Donnell (3), John Kuriyan (1)(2) Abstract: Bacterial replicative DNA polymerases such as Polymerase III (Pol III) share no sequence similarity with other polymerases. The crystal structure, determined at 2.3 A resolution, of a large fragment of Pol III (residues 1-917), reveals a unique chain fold with localized similarity in the catalytic domain to DNA polymerase [beta] and related nucleotidyltransferases. The structure of Pol III is strikingly different from those of members of the canonical DNA polymerase families, which include eukaryotic replicative polymerases, suggesting that the DNA replication machinery in bacteria arose independently. A structural element near the active site in Pol III that is not present in nucleotidyltransferases but which resembles an element at the active sites of some canonical DNA polymerases suggests that, at a more distant level, all DNA polymerases may share a common ancestor. The structure also suggests a model for interaction of Pol III with the sliding clamp and DNA. Author Affiliation: (1) Howard Hughes Medical Institute, Department of Molecular and Cell Biology and Department of Chemistry, University of California, Berkeley, CA 94720, USA (2) Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA (3) Laboratory of DNA Replication, Howard Hughes Medical Institute, The Rockefeller University, New York, NY 10021, USA Article History: Received 16 May 2006; Revised 29 June 2006; Accepted 29 July 2006 Article Note: (miscellaneous) Published: September 7, 2006

The polymerase function of 3 clinically occurring nonnucleoside reverse transcriptase inhibitor (NNRTI)-resistant RTs in greater detail, under both pre-steady-state and steady-state conditions is evaluated. Results indicate that the close proximity of the NNRTI-resistance mutations to the polymerase active site does not affect the interactions of the enzyme with the incoming nucleotide or the primer-template sufficiently to affect polymerization.

The male Sprague-Dawley rats were treated with clinically relevant doses of azidothymidine (AZT) and/or indinavir similar to those administered in humans to determine whether nucleoside reverse transcriptase inhibitors (NRTI) and/or protease inhibitors induce endothelial dysfunction. The findings suggest that in addition to the lipid disorders induced by protease inhibitors and mitochondrial DNA depletion in myocardial cells, direct endothelial dysfunction induced by AZT and perhaps other NRTIs might contribute to the development of cardiovascular complications observed in HIV patients.

The development and widespread clinical use of coformulated abacavir/lamivudine/zidovudine (ABC/3TC/ZDV) as Trizivir represented an important advance in the management of HIV‐infected patients, especially those with adherence challenges. With a low pill burden, no food restrictions, limited drug‐drug interactions, and a favorable resistance profile, ABC/3TC/ZDV remains an alternative option in the US Department of Health and Human Services Consensus Panel Guidelines as initial treatment in antiretroviral‐naive patients. Recent data have shown ABC/3TC/ZDV to be less efficacious in suppressing and/or maintaining suppression of virologic replication compared with efavirenz‐containing antiretroviral therapy. Although triple‐nucleoside/nucleotide reverse transcriptase inhibitor (t‐NRTI) combinations that do not contain a thymidine analog (ZDV or stavudine) have recently shown high virologic failure rates in clinical trials and clinical practice, t‐NRTI regimens containing a thymidine analog have consistently been shown to be efficacious., Introduction The development and widespread clinical use of coformulated abacavir/lamivudine/zidovudine (ABC/3TC/ZDV) as Trizivir represented an important advance in the management of HIV‐infected patients, especially those with adherence challenges. With a [...]

The nucleotide transition G→A is known as a hypermutation due to its high prevalence in HIV‐1 and other pathogens. However, the contribution of the G→A transition in the generation of drug resistance mutations is unknown. Our objective was to ascertain the rate of nucleotide substitutions in protease (PR) and reverse transcriptase (RT) in both untreated and treated HIV‐1 patients. Genotypic analysis was performed on viruses from both treated and untreated patients with subtype B infections. Nucleotide genomic diversity was compared with a consensus subtype B reference virus. Then, the prevalence of resistance‐associated mutations in different subgroups of treated patients was evaluated in relation to the patterns of nucleotide transitions. In untreated patients (n = 50) G→A was most prevalent, followed by A→G, C→T, and T→C transitions. In treated patients (n = 51), the prevalence of A→G was similar to that of G→A. Among mutations that confer resistance to antiretroviral drugs, M184V was present in 76% of treated patients and K70R in 31% (A→G transitions). Other frequent mutations in RT included T215Y (C→A and A→T substitutions), which was prevalent in 31% of treated patients. In PR, a L90M (T→A substitution) was prevalent in 47% of protease inhibitor (PI)‐treated patients. In conclusion, the G→A transition was most prevalent in RT and PR among untreated patients. In contrast, A→G was the most prevalent transition in patients treated with antiretroviral drugs., Introduction The genetic diversity of HIV‐1 is a subject of growing concern in regard to both diagnosis of HIV infection as well as expectations of responsiveness to antiretroviral therapy. Resistance [...]

Research elucidates the mechanism of inhibition of DNA polymerase by two phenalenone derivatives from marine-derived fungus. Results show that sculezonone-B selectively inhibits DNA pol alpha and gamma, whereas sculezonone-A inhibits pol beta. Data suggest that the different inhibition spectra is due to differences in the distribution of electrostatic potential on their molecular surfaces.

Research shows that specific amino acids within the polymerase domain mediate DNA mismatch recognition in the Klenow fragment of Escherichia coli DNA polymerase 1. Data indicate that the polymerase errors are not due to thermodynamic differences between base pairs and are eliminated by the 3'--5' exonuclease activity.

Research demonstrates that formation of DNaX complexes in the presence of ATP on primed DNA is mediated by the DNA polymerase III holoenzyme. Results show that the holoenzyme is an intrinsically asymmetric dimer with distinguishable leading and lagging strand polymerases.

The human pol alpha family ternary complex consiting of RB69 DNA polymerase complexed with primer-template DNA and a deoxynucleoside triphosphate exhibits differences and similarities to other DNA polymerases.

Research shows that mitochondrial DNA polymerase pol gamma from Drosophila consists of three domains, N,M, and C with M and C taking part in the subunit interraction and the N region modulating subunit assembly. The conformational and functional aspects of mitochondrial pol gamma complex resemble those of HIV-1 reverse transcriptase.

Results reveal that the DNA-binding domain of the rat DNA polymerase is homogeneous with a even spread of the protein-DNA contacts and no significant base specificity. Data indicate that the domain exhibits an affinity toward the double-stranded DNA conformation.

Results demonstrate that geometry of the nucleotide coupled with its ability to form Watson-Crick hydrogen bonds with the template confers stability on the closed ternary complexes of DNA polymerase. Data also indicate that ddNTP or rNTP can not mediate stable closed enzyme ternary complexes.