Cohesin-mediated interactions organize chromosomal domain architecture

To ensure proper gene regulation within constrained nuclear space, chromosomes facilitate access to transcribed regions, while compactly packaging all other information. Recent studies revealed that chromosomes are organized into megabase-scale domains that demarcate active and inactive genetic elements, suggesting that compartmentalization is important for genome function. Here, we show that very specific long-range interactions are anchored by cohesin/CTCF sites, but not cohesin-only or CTCF-only sites, to form a hierarchy of chromosomal loops. These loops demarcate topological domains and form intricate internal structures within them. Post-mitotic nuclei deficient for functional cohesin exhibit global architectural changes associated with loss of cohesin/CTCF contacts and relaxation of topological domains. Transcriptional analysis shows that this cohesin-dependent perturbation of domain organization leads to widespread gene deregulation of both cohesin-bound and non-bound genes. Our data thereby support a role for cohesin in the global organization of domain structure and suggest that domains function to stabilize the transcriptional programmes within them. Chromosomal compartmentalization has been recognized as important for genome function. High-resolution techniques such as Hi-C, ChIP- and 4C-seq offer novel insights into cohesin's dynamic role in shaping the nuclear architecture

A trial of nurse practitioner scope of practice

Aims. The aim of this paper is to report a trial to investigate the feasibility of the nurse practitioner role in local health service delivery and to provide information about the educational and legislative requirements for nurse practitioner practice. Background. Nurse practitioners have been shown to offer a beneficial service and fill a gap in health care provision. However, the lack of publications describing, critiquing, or defending the way that existing nurse practitioner roles have been developed may lead to a lack of clarity in comparing the nurse practitioner scope of practice internationally. In Australia, credible exploratory research is needed to realize the potential of nurse practitioners to bridge the divide of inequitable distribution of health services. A trial of nurse practitioner services in the Australian Capital Territory provided an excellent opportunity to investigate these scope and continuity issues. Methods. This was an observational analytic study using multiple data sources. Four models of nurse practitioner service were chosen from a competitive field of applications that were evaluated according to efficacy, feasibility, and sustainability across specified selection criteria. Each model in the trial included a clinical support team, with the nurse practitioner candidate 'working-into-the-role' and collecting demographic, clinical practice, patient outcome, and health service and consumer survey data over a 10 month period. Findings. The trial identified the broad potential of the nurse practitioner role, its breadth and limitations, and its impact on selected health services in the Australian Capital Territory. Data from individual models were compared highlighting generic elements, and formed the basis for the development of the scope of practice for the Australian Capital Territory nurse practitioner models. Conclusions. This study has validated a research-based, iterative process for initial development of nurse practitioner scope of practice for any Australian specialization. Importantly, the study concluded with the scope of practice as a finding, rather than commencing with it a priori. Although general areas of health care need and under-servicing were identified at the outset, the process tested both the expansion and parameters of the roles. What is already known about this topic: • Nurse practitioners offer a beneficial service and fill a gap in health care provision. • The nurse practitioner scope of practice varies from country to country. • Australian nurse practitioners are well positioned to bridge the divide of inequitable distribution of health services not only between metropolitan and rural/remote areas, but also within metropolitan areas. What this paper adds: • Research-based, iterative processes for development of clinical protocols that define the scope of practice for diverse nurse practitioner models. • A test of both the expansion and parameters of the roles applicable for any Australian specialization. • Systems and processes to inform health policy deliberations