Interaction domains of the UL16 and UL21 tegument proteins of herpes simplex virus.

The UL16 protein of herpes simplex virus is capsid associated and was previously identified as a binding partner of the membrane-associated UL11 tegument protein (J. S. Loomis, R. J. Courtney, and J. W. Wills, J. Virol. 77:11417-11424, 2003). In those studies, a less-prominent, approximately 65-kDa binding partner of unknown identity was also observed. Mass spectrometry studies have now revealed this species to be UL21, a tegument protein that has been implicated in the transport of capsids in the cytoplasm. The validity of the mass spectrometry results was tested in a variety of coimmunoprecipitation and glutathione S-transferase pull-down experiments. The data revealed that UL21 and UL16 can form a complex in the absence of other viral proteins, even when the assays used proteins purified from Escherichia coli. Moreover, UL11 was able to pull down UL21 only when UL16 was present, suggesting that all three proteins can form a complex. Deletion analyses revealed that the second half of UL21 (residues 268 to 535) is sufficient for the UL16 interaction and packaging into virions; however, attempts to map a subdomain of UL16 were largely unsuccessful, with only the first 40 (of 373) residues being found to be dispensable. Nevertheless, it is clear that UL16 must have two distinct binding sites, because covalent modification of its free cysteines with N-ethylmaleimide blocked binding to UL11 but not UL21. These findings should prove useful for elucidating the molecular machinery used to transmit a signal into a virion when it attaches to cells, a recently discovered mechanism in which UL16 is a central player.

A Systematic Review of Tools Used to Assess Team Leadership in Health Care Action Teams.

PURPOSE: To summarize the characteristics of tools used to assess leadership in health care action (HCA) teams. HCA teams are interdisciplinary teams performing complex, critical tasks under high-pressure conditions. METHOD: The authors conducted a systematic review of the PubMed/MEDLINE, CINAHL, ERIC, EMBASE, PsycINFO, and Web of Science databases, key journals, and review articles published through March 2012 for English-language articles that applied leadership assessment tools to HCA teams in all specialties. Pairs of reviewers assessed identified articles for inclusion and exclusion criteria and abstracted data on study characteristics, tool characteristics, and validity evidence. RESULTS: Of the 9,913 abstracts screened, 83 studies were included. They described 61 team leadership assessment tools. Forty-nine tools (80%) provided behaviors, skills, or characteristics to define leadership. Forty-four tools (72%) assessed leadership as one component of a larger assessment, 13 tools (21%) identified leadership as the primary focus of the assessment, and 4 (7%) assessed leadership style. Fifty-three studies (64%) assessed leadership at the team level; 29 (35%) did so at the individual level. Assessments of simulated (n = 55) and live (n = 30) patient care events were performed. Validity evidence included content validity (n = 75), internal structure (n = 61), relationship to other variables (n = 44), and response process (n = 15). CONCLUSIONS: Leadership assessment tools applied to HCA teams are heterogeneous in content and application. Comparisons between tools are limited by study variability. A systematic approach to team leadership tool development, evaluation, and implementation will strengthen understanding of this important competency.

Leadership training in health care action teams: a systematic review.

PURPOSE: To identify and describe the design, implementation, and evidence of effectiveness of leadership training interventions for health care action (HCA) teams, defined as interdisciplinary teams whose members coordinate their actions in time-pressured, unstable situations. METHOD: The authors conducted a systematic search of the PubMed/MEDLINE, CINAHL, ERIC, EMBASE, PsycINFO, and Web of Science databases, key journals, and review articles published through March 2012. They identified peer-reviewed English-language articles describing leadership training interventions targeting HCA teams, at all levels of training and across all health care professions. Reviewers, working in duplicate, abstracted training characteristics and outcome data. Methodological quality was evaluated using the Medical Education Research Study Quality Instrument (MERSQI). RESULTS: Of the 52 included studies, 5 (10%) focused primarily on leadership training, whereas the remainder included leadership training as part of a larger teamwork curriculum. Few studies reported using a team leadership model (2; 4%) or a theoretical framework (9; 17%) to support their curricular design. Only 15 studies (29%) specified the leadership behaviors targeted by training. Forty-five studies (87%) reported an assessment component; of those, 31 (69%) provided objective outcome measures including assessment of knowledge or skills (21; 47%), behavior change (8; 18%), and patient- or system-level metrics (8; 18%). The mean MERSQI score was 11.4 (SD 2.9). CONCLUSIONS: Leadership training targeting HCA teams has become more prevalent. Determining best practices in leadership training is confounded by variability in leadership definitions, absence of supporting frameworks, and a paucity of robust assessments.

A substitution in rous sarcoma virus integrase that separates its two biologically relevant enzymatic activities.

Retroviral integrase prepares viral DNA for integration by removing 2 nucleotides from each end of unintegrated DNA in a reaction referred to as processing. However, it has been known since the processing assay was first described that avian integrases frequently nick 3 nucleotides, as well as 2 nucleotides, from viral DNA ends when reaction mixtures contain Mn2+. We now report that specificity for the biologically relevant "-2" site is enhanced when the serine at amino acid 124 of Rous sarcoma virus (RSV) integrase is replaced by alanine, valine, glycine, lysine, or aspartate. The protein with a serine-to-aspartate substitution exhibited especially high fidelity for the correct site, as evidenced by a ratio of -2 nicks to -3 nicks that was more than 40-fold greater than that for the wild-type enzyme in reactions with Mn2+. Even with Mg2+, the substituted proteins exhibited greater specificity than the wild type, especially the S124D protein. Moreover, this protein was more efficient than the wild type at processing viral DNA ends. Unexpectedly, however, the S124D protein was significantly impaired at catalyzing the insertion of viral DNA ends in reactions with Mn2+ and joining was undetectable in reactions with Mg2+. Thus, the S124D protein has separated the processing and joining activities of integrase. Similar results were found for human immunodeficiency virus integrase with the analogous substitution. No proteins with comparable properties have been described. Moreover, RSV virions containing integrase with the S124D mutation were unable to replicate in cell cultures. Together, these data suggest that integrase has evolved to have submaximal processing activity so that it can also catalyze DNA joining.

An amino acid in the central catalytic domain of three retroviral integrases that affects target site selection in nonviral DNA.

Integrase can insert retroviral DNA into almost any site in cellular DNA; however, target site preferences are noted in vitro and in vivo. We recently demonstrated that amino acid 119, in the alpha2 helix of the central domain of the human immunodeficiency virus type 1 integrase, affected the choice of nonviral target DNA sites. We have now extended these findings to the integrases of a nonprimate lentivirus and a more distantly related alpharetrovirus. We found that substitutions at the analogous positions in visna virus integrase and Rous sarcoma virus integrase changed the target site preferences in five assays that monitor insertion into nonviral DNA. Thus, the importance of this protein residue in the selection of nonviral target DNA sites is likely to be a general property of retroviral integrases. Moreover, this amino acid might be part of the cellular DNA binding site on integrase proteins.