An investigation into factors affecting condensin association with mitotic centromeres

The SMC protein family (Structural Maintenance of Chromosomes) consists of a group of highly conserved protein complexes, central to chromosome dynamics and key cell cycle events. Condensin is a member of the SMC protein family, best known for its role in chromosome condensation and segregation in mitosis. The condensin complex becomes enriched at specific chromosome loci in a cell-cycle specific manner. However, the details of how it becomes associated with chromatin remain unclear. A particular area of interest regarding condensin association and activity is at the centromeres and pericentromeres, where condensin has been consistently shown to be enriched specifically during mitosis. This work is comprised of four results chapters, investigating factors affecting condensin association with mitotic centromeres in Saccharomyces cerevisiae, using chromatin immunoprecipitation (ChIP). We started by establishing a robust ChIP assay suitable for probing condensin enrichment at the centromeric regions. We conducted genetic control experiments to ensure the functionality of the experimental technique. In the next chapter we explored the importance of the kinetochore with regards to condensin enrichment, and found that perturbing the budding yeast kinetochore results in a loss of centromeric condensin association during mitosis. We then used condensin phosphorylation site and mitotic kinase mutants to examine the role of condensin subunit phosphorylation in its association with chromatin. Our results showed that Ipl1 (Aurora B kinase) and condensin phosphorylation is important for its enrichment at the centromere, but rather surprisingly that Cdc5 (polo-like kinase) a known activator of condensin does not appear to be. The final chapter investigates the function of condensin’s intrinsic ATPase activity, and we found that ATP-binding activity but not ATP-hydrolysis is important for condensin association with chromatin

SMC complexes differentially compact mitotic chromosomes according to genomic context

Structural maintenance of chromosomes (SMC) protein complexes are key determinants of chromosome conformation. Using Hi-C and polymer modelling, we study how cohesin and condensin, two deeply conserved SMC complexes, organize chromosomes in the budding yeast Saccharomyces cerevisiae. The canonical role of cohesin is to co-align sister chromatids, while condensin generally compacts mitotic chromosomes. We find strikingly different roles for the two complexes in budding yeast mitosis. First, cohesin is responsible for compacting mitotic chromosome arms, independently of sister chromatid cohesion. Polymer simulations demonstrate that this role can be fully accounted for through cis-looping of chromatin. Second, condensin is generally dispensable for compaction along chromosome arms. Instead, it plays a targeted role compacting the rDNA proximal regions and promoting resolution of peri-centromeric regions. Our results argue that the conserved mechanism of SMC complexes is to form chromatin loops and that distinct SMC-dependent looping activities are selectively deployed to appropriately compact chromosomes

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Uterine-Preserving Surgeries for the Repair of Pelvic Organ Prolapse: A Systematic Review with Meta-Analysis and Clinical Practice Guidelines

INTRODUCTION AND HYPOTHESIS: We aimed to systematically review the literature on pelvic organ prolapse (POP) surgery with uterine preservation (hysteropexy). We hypothesized that different hysteropexy surgeries would have similar POP outcomes but varying adverse event (AE) rates. METHODS: MEDLINE, Cochrane, and clinicaltrials.gov databases were reviewed from inception to January 2018 for comparative (any size) and single-arm studies (n \u3e/= 50) involving hysteropexy. Studies were extracted for participant characteristics, interventions, comparators, outcomes, and AEs and assessed for methodological quality. RESULTS: We identified 99 eligible studies: 53 comparing hysteropexy to POP surgery with hysterectomy, 42 single-arm studies on hysteropexy, and four studies comparing stage \u3e/=2 hysteropexy types. Data on POP outcomes were heterogeneous and usually from \u3c3 years of follow-up. Repeat surgery prevalence for POP after hysteropexy varied widely (0-29%) but was similar among hysteropexy types. When comparing sacrohysteropexy routes, the laparoscopic approach had lower recurrent prolapse symptoms [odds ratio (OR) 0.18, 95% confidence interval (CI) 0.07-0.46), urinary retention (OR 0.05, 95% CI 0.003-0.83), and blood loss (difference -104 ml, 95% CI -145 to -63 ml) than open sacrohysteropexy. Laparoscopic sacrohysteropexy had longer operative times than vaginal mesh hysteropexy (difference 119 min, 95% CI 102-136 min). Most commonly reported AEs included mesh exposure (0-39%), urinary retention (0-80%), and sexual dysfunction (0-48%). CONCLUSIONS: Hysteropexies have a wide range of POP recurrence and AEs; little data exist directly comparing different hysteropexy types. Therefore, for women choosing uterine preservation, surgeons should counsel them on outcomes and risks particular to the specific hysteropexy type planned

A Guide for Urogynecologic Patient Care Utilizing Telemedicine During the COVID-19 Pandemic: Review of Existing Evidence

INTRODUCTION AND HYPOTHESIS: The COVID-19 pandemic and the desire to flatten the curve of transmission have significantly affected the way providers care for patients. Female Pelvic Medicine and Reconstructive Surgeons (FPMRS) must provide high quality of care through remote access such as telemedicine. No clear guidelines exist on the use of telemedicine in FPMRS. Using expedited literature review methodology, we provide guidance regarding management of common outpatient urogynecology scenarios during the pandemic. METHODS: We grouped FPMRS conditions into those in which virtual management differs from direct in-person visits and conditions in which treatment would emphasize behavioral and conservative counseling but not deviate from current management paradigms. We conducted expedited literature review on four topics (telemedicine in FPMRS, pessary management, urinary tract infections, urinary retention) and addressed four other topics (urinary incontinence, prolapse, fecal incontinence, defecatory dysfunction) based on existing systematic reviews and guidelines. We further compiled expert consensus regarding management of FPMRS patients in the virtual setting, scenarios when in-person visits are necessary, symptoms that should alert providers, and specific considerations for FPMRS patients with suspected or confirmed COVID-19. RESULTS: Behavioral, medical, and conservative management will be valuable as first-line virtual treatments. Certain situations will require different treatments in the virtual setting while others will require an in-person visit despite the risks of COVID-19 transmission. CONCLUSIONS: We have presented guidance for treating FPMRS conditions via telemedicine based on rapid literature review and expert consensus and presented it in a format that can be actively referenced

A Guide for Urogynecologic Patient Care Utilizing Telemedicine During the COVID-19 Pandemic: Review of Existing Evidence

INTRODUCTION AND HYPOTHESIS: The COVID-19 pandemic and the desire to flatten the curve of transmission have significantly affected the way providers care for patients. Female Pelvic Medicine and Reconstructive Surgeons (FPMRS) must provide high quality of care through remote access such as telemedicine. No clear guidelines exist on the use of telemedicine in FPMRS. Using expedited literature review methodology, we provide guidance regarding management of common outpatient urogynecology scenarios during the pandemic. METHODS: We grouped FPMRS conditions into those in which virtual management differs from direct in-person visits and conditions in which treatment would emphasize behavioral and conservative counseling but not deviate from current management paradigms. We conducted expedited literature review on four topics (telemedicine in FPMRS, pessary management, urinary tract infections, urinary retention) and addressed four other topics (urinary incontinence, prolapse, fecal incontinence, defecatory dysfunction) based on existing systematic reviews and guidelines. We further compiled expert consensus regarding management of FPMRS patients in the virtual setting, scenarios when in-person visits are necessary, symptoms that should alert providers, and specific considerations for FPMRS patients with suspected or confirmed COVID-19. RESULTS: Behavioral, medical, and conservative management will be valuable as first-line virtual treatments. Certain situations will require different treatments in the virtual setting while others will require an in-person visit despite the risks of COVID-19 transmission. CONCLUSIONS: We have presented guidance for treating FPMRS conditions via telemedicine based on rapid literature review and expert consensus and presented it in a format that can be actively referenced