The Interdomain Linker of AAV-2 Rep68 Is an Integral Part of Its Oligomerization Domain: Role of a Conserved SF3 Helicase Residue in Oligomerization

The four Rep proteins of adeno-associated virus (AAV) orchestrate all aspects of its viral life cycle, including transcription regulation, DNA replication, virus assembly, and site-specific integration of the viral genome into the human chromosome 19. All Rep proteins share a central SF3 superfamily helicase domain. In other SF3 members this domain is sufficient to induce oligomerization. However, the helicase domain in AAV Rep proteins (i.e. Rep40/Rep52) as shown by its monomeric characteristic, is not able to mediate stable oligomerization. This observation led us to hypothesize the existence of an as yet undefined structural determinant that regulates Rep oligomerization. In this document, we described a detailed structural comparison between the helicase domains of AAV-2 Rep proteins and those of the other SF3 members. This analysis shows a major structural difference residing in the small oligomerization sub-domain (OD) of Rep helicase domain. In addition, secondary structure prediction of the linker connecting the helicase domain to the origin-binding domain (OBD) indicates the potential to form α-helices. We demonstrate that mutant Rep40 constructs containing different lengths of the linker are able to form dimers, and in the presence of ATP/ADP, larger oligomers. We further identified an aromatic linker residue (Y224) that is critical for oligomerization, establishing it as a conserved signature motif in SF3 helicases. Mutation of this residue critically affects oligomerization as well as completely abolishes the ability to produce infectious virus. Taken together, our data support a model where the linker residues preceding the helicase domain fold into an α-helix that becomes an integral part of the helicase domain and is critical for the oligomerization and function of Rep68/78 proteins through cooperative interaction with the OBD and helicase domains

Balancing repair and tolerance of DNA damage caused by alkylating agents

Alkylating agents constitute a major class of frontline chemotherapeutic drugs that inflict cytotoxic DNA damage as their main mode of action, in addition to collateral mutagenic damage. Numerous cellular pathways, including direct DNA damage reversal, base excision repair (BER) and mismatch repair (MMR), respond to alkylation damage to defend against alkylation-induced cell death or mutation. However, maintaining a proper balance of activity both within and between these pathways is crucial for a favourable response of an organism to alkylating agents. Furthermore, the response of an individual to alkylating agents can vary considerably from tissue to tissue and from person to person, pointing to genetic and epigenetic mechanisms that modulate alkylating agent toxicity

Long-term behavior and quality of life after corrective cardiac surgery in infancy for tetralogy of Fallot or ventricular septal defect.

The objective of this study was to evaluate behavior and quality of life in children after corrective cardiac surgery in infancy. Twenty cyanotic (tetralogy of Fallot) and 20 acyanotic children (ventricular septal defect), operated at a mean age of 0.7 years with deep hypothermic circulatory arrest (DHCA) and low-flow cardiopulmonary bypass (CPB), were assessed at a mean age of 7.4 years by the Child Behavior Checklist (CBCL) and the German KINDL. Test results were related to perioperative and neurodevelopmental outcome. Compared to healthy children and not significantly different between the groups, internalizing and externalizing problems were elevated, school performance and total competence were reduced, and self- and parent-reported quality of life was not reduced. Parent-reported problems and reduced physical status were correlated with longer durations of DHCA and CPB. Internalizing and externalizing problems, reduced school competence, and reduced self-esteem were associated with reduced endurance capacity. Externalizing problems were related to reduced gross motor function. Poor school competence was related to reduced intelligence and academic achievement. Children with preoperative hypoxemia in infancy due to cyanotic cardiac defects are not at significantly higher risk for behavioral problems and reduced quality of life than those with acyanotic heart defects. The risk of long-term psychosocial maladjustment after corrective surgery in infancy is increased compared to that for normal children and related to the presence of neurodevelopmental dysfunction

Survival after cancer in Italian persons with AIDS, 1996-2005: a population-based estimation

Background: Cancer survival in persons with AIDS (PWA) after introduction of antiretroviral therapies remains poorly characterized. The aim is to provide population-based estimates of cancer survival, overall and for the most important cancer types in PWA, and a comparison with persons without AIDS (non-PWA) affected by the same cancer. Methods: PWA with cancer at AIDS diagnosis or thereafter were individually matched with non-PWA by type of cancer, sex, age, year of diagnosis, area of living, and, for lymphomas, histological subtype. Five-year observed survival and hazard ratios (HRs) of death in PWA versus non-PWA with 95% confidence intervals (CIs) were estimated. Results: We included 2262 Italian PWA and 4602 non-PWA with cancer diagnosed during 1986–2005. Between 1986 and 1995, and 1996 and 2005, 5-year survival for all cancers in PWA improved from 12% to 41% and the corresponding HR versus non-PWA decreased from 5.1 (95% CI: 4.3 to 6.1) to 2.9 (95% CI: 2.6 to 3.3). During 1996–2005, HRs were 2.0 (95% CI: 1.4 to 2.9) for Kaposi sarcoma, 3.4 (95% CI: 2.9 to 4.1) for non-Hodgkin lymphoma, and 2.4 (95% CI: 1.4 to 4.0) for cervical cancer. HRs were 2.5 (95% CI: 2.1 to 3.1) for all non–AIDS-defining cancers, 5.9 (95% CI: 3.1 to 11.2) for Hodgkin lymphoma, and 7.3 (95% CI: 2.8 to 19.2) for nonmelanoma skin cancer. A ≤3-fold survival difference was found for cancers of the stomach, liver, anus, lung, brain, and the most aggressive lymphoma subtypes. Conclusions: The persisting, although narrowing, gap in cancer survival between PWA and non-PWA indicates the necessity of enhancing therapeutic approaches, so that PWA can be provided the same chances of survival observed in the general population, and improving cancer prevention and screening

Survival after cancer in Italian persons with AIDS, 1986-2005: A population-based estimation.

BACKGROUND: Cancer survival in persons with AIDS (PWA) after introduction of antiretroviral therapies remains poorly characterized. The aim is to provide population-based estimates of cancer survival, overall and for the most important cancer types in PWA, and a comparison with persons without AIDS (non-PWA) affected by the same cancers. METHODS: PWA with cancer at AIDS or thereafter were individually matched with non-PWA by type of cancer, sex, age, year of diagnosis, area of living and, for lymphomas, histological subtype. Five-year observed survival and hazard ratios (HRs) of death in PWA versus non-PWA with 95% confidence intervals (CI) were estimated. RESULTS: We included 2262 Italian PWA and 4602 non-PWA with cancer diagnosed during 1986-2005. Between 1986-1995 and 1996-2005, 5-year survival for all cancers in PWA improved from 12% to 41% and the corresponding HR versus non-PWA decreased from 5.1 (95% CI: 4.3-6.1) to 2.9 (95% CI: 2.6-3.3). In 1996-2005, HRs were 2.0 (95% CI: 1.4-2.9) for Kaposi sarcoma; 3.4 (2.9-4.1) for non-Hodgkin lymphoma; 2.4 (1.4-4.0) for cervical cancer. HRs were 2.5 (2.1-3.1) for all non-AIDS-defining cancers; 5.9 (3.1-11.2) for Hodgkin lymphoma; and 7.3 (2.8-19.2) for non-melanoma skin. A ≤3-fold survival difference was found for cancer of the stomach, liver, anus, lung, brain and the most aggressive lymphoma subtypes. CONCLUSION(S): The persisting, although narrowing, gap in cancer survival between PWA and non-PWA indicates the necessity of enhancing therapeutic approaches, so that PWA will be provided the same chances of survival observed in the general population, and improving cancer prevention and screening

Survival after cancer in Italian persons with AIDS, 1986-2005: a population-based estimation.

Abstract BACKGROUND: Cancer survival in persons with AIDS (PWA) after introduction of antiretroviral therapies remains poorly characterized. The aim is to provide population-based estimates of cancer survival, overall and for the most important cancer types in PWA, and a comparison with persons without AIDS (non-PWA) affected by the same cancer. METHODS: PWA with cancer at AIDS diagnosis or thereafter were individually matched with non-PWA by type of cancer, sex, age, year of diagnosis, area of living, and, for lymphomas, histological subtype. Five-year observed survival and hazard ratios (HRs) of death in PWA versus non-PWA with 95% confidence intervals (CIs) were estimated. RESULTS: We included 2262 Italian PWA and 4602 non-PWA with cancer diagnosed during 1986-2005. Between 1986 and 1995, and 1996 and 2005, 5-year survival for all cancers in PWA improved from 12% to 41% and the corresponding HR versus non-PWA decreased from 5.1 (95% CI: 4.3 to 6.1) to 2.9 (95% CI: 2.6 to 3.3). During 1996-2005, HRs were 2.0 (95% CI: 1.4 to 2.9) for Kaposi sarcoma, 3.4 (95% CI: 2.9 to 4.1) for non-Hodgkin lymphoma, and 2.4 (95% CI: 1.4 to 4.0) for cervical cancer. HRs were 2.5 (95% CI: 2.1 to 3.1) for all non-AIDS-defining cancers, 5.9 (95% CI: 3.1 to 11.2) for Hodgkin lymphoma, and 7.3 (95% CI: 2.8 to 19.2) for nonmelanoma skin cancer. A 643-fold survival difference was found for cancers of the stomach, liver, anus, lung, brain, and the most aggressive lymphoma subtypes. CONCLUSIONS: The persisting, although narrowing, gap in cancer survival between PWA and non-PWA indicates the necessity of enhancing therapeutic approaches, so that PWA can be provided the same chances of survival observed in the general population, and improving cancer prevention and screening