The architecture of clonal expansions in morphologically normal tissue from cancerous and non-cancerous prostates.

Background: Up to 80% of cases of prostate cancer present with multifocal independent tumour lesions leading to the concept of a field effect present in the normal prostate predisposing to cancer development. In the present study we applied Whole Genome DNA Sequencing (WGS) to a group of morphologically normal tissue (n = 51), including benign prostatic hyperplasia (BPH) and non-BPH samples, from men with and men without prostate cancer. We assess whether the observed genetic changes in morphologically normal tissue are linked to the development of cancer in the prostate.

Long term clinical outcomes of patients with ischemic stroke in primary care - a 9-year retrospective study.

Background: We aim to document the long-term outcomes of ischemic stroke patients and explore the potential risk factors for recurrent cardiovascular events and all-cause mortality in primary care.

Methods: A retrospective cohort study performed at two general out-patient clinics (GOPCs) under Hospital Authority (HA) in Hong Kong (HK). Ischemic stroke patients with at least two consecutive follow-up visits during the recruitment period (1/1-30/6/2010) were included.

Clinical Audit on Chronic Obstructive Pulmonary Disease (COPD) Management in Primary Care: A Quality Improvement Project from Hong Kong.

Objective: To enhance the quality of COPD management in primary care via a two-phase clinical audit in Hong Kong.

Methods: COPD patients aged 40 or above and had attended any of the 73 public primary care clinics under the Hospital Authority of Hong Kong (HAHK) for follow up (FU) during the audit period were included. Performance of six evidence-based audit criteria on COPD care was reviewed in phase 1 from 1st April 2017 to 31st March 2018.

Fundamental cell cycle kinases collaborate to ensure timely destruction of the synaptonemal complex during meiosis.

The synaptonemal complex (SC) is a proteinaceous macromolecular assembly that forms during meiotic prophase I and mediates adhesion of paired homologous chromosomes along their entire lengths. Although prompt disassembly of the SC during exit from prophase I is a landmark event of meiosis, the underlying mechanism regulating SC destruction has remained elusive. Here, we show that DDK (Dbf4-dependent Cdc7 kinase) is central to SC destruction.

The synaptonemal complex is assembled by a polySUMOylation-driven feedback mechanism in yeast.

During meiotic prophase I, proteinaceous structures called synaptonemal complexes (SCs) connect homologous chromosomes along their lengths via polymeric arrays of transverse filaments (TFs). Thus, control of TF polymerization is central to SC formation. Using budding yeast, we show that efficiency of TF polymerization closely correlates with the extent of SUMO conjugation to Ecm11, a component of SCs.

Direct and indirect control of the initiation of meiotic recombination by DNA damage checkpoint mechanisms in budding yeast.

Meiotic recombination plays an essential role in the proper segregation of chromosomes at meiosis I in many sexually reproducing organisms. Meiotic recombination is initiated by the scheduled formation of genome-wide DNA double-strand breaks (DSBs). The timing of DSB formation is strictly controlled because unscheduled DSB formation is detrimental to genome integrity.

The Ecm11-Gmc2 complex promotes synaptonemal complex formation through assembly of transverse filaments in budding yeast.

During meiosis, homologous chromosomes pair at close proximity to form the synaptonemal complex (SC). This association is mediated by transverse filament proteins that hold the axes of homologous chromosomes together along their entire length. Transverse filament proteins are highly aggregative and can form an aberrant aggregate called the polycomplex that is unassociated with chromosomes.

Budding yeast Pch2, a widely conserved meiotic protein, is involved in the initiation of meiotic recombination.

Budding yeast Pch2 protein is a widely conserved meiosis-specific protein whose role is implicated in the control of formation and displacement of meiotic crossover events. In contrast to previous studies where the function of Pch2 was implicated in the steps after meiotic double-strand breaks (DSBs) are formed, we present evidence that Pch2 is involved in meiotic DSB formation, the initiation step of meiotic recombination. The reduction of DSB formation caused by the pch2 mutation is most prominent in the sae2 mutant background, whereas the impact remains mild in the rad51 dmc1 double mutant background.

Characterization of meiotic recombination initiation sites using pulsed-field gel electrophoresis.

High levels of homologous recombination are induced during meiosis. This meiotic recombination is initiated by programmed formation of DNA double-strand breaks (DSBs) by a conserved meiosis-specific protein, Spo11. Meiotic DSBs are not formed at random along chromosomes but are formed in clusters known as recombination hot spots.

The budding yeast Mei5-Sae3 complex interacts with Rad51 and preferentially binds a DNA fork structure.

Meiotic homologous recombination in Saccharomyces cerevisiae involves formation of nucleoprotein filaments of Rad51 and Dmc1 that mediate DNA strand exchange between homologous chromosomes. The Mei5-Sae3 protein complex functions as a recombination mediator to promote nucleation of the Dmc1 recombinase onto replication protein A-coated single-stranded DNA. Here, we have expressed and purified the Mei5 protein, Sae3 protein and the Mei5-Sae3 complex for biochemical studies.