Alternative splicing and protein diversity: plants versus animals

Plants, unlike animals, exhibit a very high degree of plasticity in their growth and development and employ diverse strategies to cope with the variations during diurnal cycles and stressful conditions. Plants and animals, despite their remarkable morphological and physiological differences, share many basic cellular processes and regulatory mechanisms. Alternative splicing (AS) is one such gene regulatory mechanism that modulates gene expression in multiple ways. It is now well established that AS is prevalent in all multicellular eukaryotes including plants and humans. Emerging evidence indicates that in plants, as in animals, transcription and splicing are coupled. Here, we reviewed recent evidence in support of co-transcriptional splicing in plants and highlighted similarities and differences between plants and humans. An unsettled question in the field of AS is the extent to which splice isoforms contribute to protein diversity. To take a critical look at this question, we presented a comprehensive summary of the current status of research in this area in both plants and humans, discussed limitations with the currently used approaches and suggested improvements to current methods and alternative approaches. We end with a discussion on the potential role of epigenetic modifications and chromatin state in splicing memory in plants primed with stresses

Lamin Mutations Cause Increased YAP Nuclear Entry in Muscle Stem Cells

Mutations in the LMNA gene, encoding the nuclear envelope A-type lamins, are responsible for muscular dystrophies, the most severe form being the LMNA-related congenital muscular dystrophy (L-CMD), with severe defects in myonucleus integrity. We previously reported that L-CMD mutations compromise the ability of muscle stem cells to modulate the yes-associated protein (YAP), a pivotal factor in mechanotransduction and myogenesis. Here, we investigated the intrinsic mechanisms by which lamins influence YAP subcellular distribution, by analyzing different conditions affecting the balance between nuclear import and export of YAP. In contrast to wild type (WT) cells, LMNADK32 mutations failed to exclude YAP from the nucleus and to inactivate its transcriptional activity at high cell density, despite activation of the Hippo pathway. Inhibiting nuclear pore import abolished YAP nuclear accumulation in confluent mutant cells, thus showing persistent nuclear import of YAP at cell confluence. YAP deregulation was also present in congenital myopathy related to nesprin-1KASH mutation, but not in cells expressing the LMNAH222P mutation, the adult form of lamin-related muscle dystrophy with reduced nuclear deformability. In conclusion, our data showed that L-CMD mutations increased YAP nuclear localization via an increased nuclear import and implicated YAP as a pathogenic contributor in muscle dystrophies caused by nuclear envelop defects

Does co-transcriptional regulation of alternative splicing mediate plant stress responses?

Plants display exquisite control over gene expression to elicit appropriate responses under normal and stress conditions. Alternative splicing (AS) of pre-mRNAs, a process that generates two or more transcripts from multi-exon genes, adds another layer of regulation to fine-tune condition-specific gene expression in animals and plants. However, exactly how plants control splice isoform ratios and the timing of this regulation in response to environmental signals remains elusive. In mammals, recent evidence indicate that epigenetic and epitranscriptome changes, such as DNA methylation, chromatin modifications and RNA methylation, regulate RNA polymerase II processivity, co-transcriptional splicing, and stability and translation efficiency of splice isoforms. In plants, the role of epigenetic modifications in regulating transcription rate and mRNA abundance under stress is beginning to emerge. However, the mechanisms by which epigenetic and epitranscriptomic modifications regulate AS and translation efficiency require further research. Dynamic changes in the chromatin landscape in response to stress may provide a scaffold around which gene expression, AS and translation are orchestrated. Finally, we discuss CRISPR/Cas-based strategies for engineering chromatin architecture to manipulate AS patterns (or splice isoforms levels) to obtain insight into the epigenetic regulation of AS

Differential nucleosome occupancy modulates alternative splicing in Arabidopsis thaliana

• Alternative splicing (AS) is a major gene regulatory mechanism in plants. Recent evidence supports co-transcriptional splicing in plants, hence the chromatin state can impact AS. However, how dynamic changes in the chromatin state such as nucleosome occupancy influence the cold-induced AS remains poorly understood. • Here, we generated transcriptome (RNA-Seq) and nucleosome positioning (MNase-Seq) data for Arabidopsis thaliana to understand how nucleosome positioning modulates cold-induced AS. • Our results show that characteristic nucleosome occupancy levels are strongly associated with the type and abundance of various AS events under normal and cold temperature conditions in Arabidopsis. Intriguingly, exitrons, alternatively spliced internal regions of protein-coding exons, exhibit distinctive nucleosome positioning pattern compared to other alternatively spliced regions. Likewise, nucleosome patterns differ between exitrons and retained introns pointing to their distinct regulation. • Collectively, our data show that characteristic changes in nucleosome positioning modulate AS in plants in response to cold

Family History of Non-communicable Disease and its Relationship in Acute Coronary Syndrome with or without Diabetes Mellitus

Worldwide, non-communicable diseases which involve heart disease, diabetes mellitus and hypertension, represent a major risk factor that increases morbidity and mortality of acute coronary syndrome (ACS). The Objective of this study is to assess the Association of family history of non-communicable diseases in ACS patients with diabetes mellitus. This study is descriptive study of 175 ACS patients reported to the cardiology department in a tertiary care center in Ajman, UAE. Patient records were viewed on the computer database and all the necessary information required to achieve the objectives were extracted and filled in the checklist prepared. The data was analyzed by SPSS 20 and Chi square test was done to assess the association. The results shows that the non-communicable diseases reported were diabetes mellitus, hypertension and heart diseases. The degree of relation was divided into first and second degrees. The first degree of relation included (father, mother, brother, sister or more than one of them. The second degree of relation included (uncle, cousin, aunt, grandfather, grandmother etc.). There were 11(91.7%) patients with first degree family history of DM and 1(8.3%) patient with second degree relation. Out of the 14 patients that gave positive family history of hypertension only one was second degree of relation and all the rest were first degree of relation. Regarding the most common non-communicable disease, heart disease, 18(94.7%) patients had first degree relatives and 1(5.3%) second degree relative with history of heart disease. As a conclusion we can say that among the ACS patients with family history of heart diseases, majority of them (94.7%) had in first degree relatives whereas in the case of family history of hypertension and diabetes, it was also highly reported in first degree relatives with 92.9% and 91.7% respectively. It was also found family history of DM has a major role for the occurrence of DM in ACS patients

Effects of varying case definition on carpal tunnel syndrome prevalence estimates in a pooled cohort

OBJECTIVE: To analyze differences in carpal tunnel syndrome (CTS) prevalence using a combination of electrodiagnostic studies (EDSs) and symptoms using EDS criteria varied across a range of cutpoints and compared with symptoms in both ≥1 and ≥2 median nerve–served digits. DESIGN: Pooled data from 5 prospective cohorts. SETTING: Hand-intensive industrial settings, including manufacturing, assembly, production, service, construction, and health care. PARTICIPANTS: Employed, working-age participants who are able to provide consent and undergo EDS testing (N=3130). INTERVENTIONS: None. MAIN OUTCOME MEASURES: CTS prevalence was estimated while varying the thresholds for median sensory latency, median motor latency, and transcarpal delta latency difference. EDS criteria examined included the following: median sensory latency of 3.3 to 4.1 milliseconds, median motor latency of 4.1 to 4.9 milliseconds, and median-ulnar sensory difference of 0.4 to 1.2 milliseconds. EDS criteria were combined with symptoms in ≥1 or ≥2 median nerve–served digits. EDS criteria from other published studies were applied to allow for comparison. RESULTS: CTS prevalence ranged from 6.3% to 11.7%. CTS prevalence estimates changed most per millisecond of sensory latency compared with motor latency or transcarpal delta. CTS prevalence decreased by 0.9% to 2.0% if the criteria required symptoms in 2 digits instead of 1. CONCLUSIONS: There are meaningful differences in CTS prevalence when different EDS criteria are applied. The digital sensory latency criteria result in the largest variance in prevalence

Healthcare professionals' intentions to use wiki-based reminders to promote best practices in trauma care: a survey protocol

<p>Abstract</p> <p>Background</p> <p>Healthcare professionals are increasingly using wikis as collaborative tools to create, synthesize, share, and disseminate knowledge in healthcare. Because wikis depend on collaborators to keep content up-to-date, healthcare professionals who use wikis must adopt behaviors that foster this collaboration. This protocol describes the methods we will use to develop and test the metrological qualities of a questionnaire that will assess healthcare professionals' intentions and the determinants of those intentions to use wiki-based reminders that promote best practices in trauma care.</p> <p>Methods</p> <p>Using the Theory of Planned Behavior, we will conduct semi-structured interviews of healthcare professionals to identify salient beliefs that may affect their future use of wikis. These beliefs will inform our questionnaire on intended behavior. A test-retest of the survey will verify the questionnaire's stability over time. We will interview 50 healthcare professionals (25 physicians and 25 allied health professionals) working in the emergency departments of three trauma centers in Quebec, Canada. We will analyze the content of the interviews and construct and pilot a questionnaire. We will then test the revised questionnaire with 30 healthcare professionals (15 physicians and 15 allied health professionals) and retest it two weeks later. We will assess the internal consistency of the questionnaire constructs using Cronbach's alpha coefficients and determine their stability with the intra-class correlation (ICC).</p> <p>Discussion</p> <p>To our knowledge, this study will be the first to develop and test a theory-based survey that measures healthcare professionals' intentions to use a wiki-based intervention. This study will identify professionals' salient beliefs qualitatively and will quantify the psychometric capacities of the questionnaire based on those beliefs.</p

Sulfur-Directed Olefin Oxidations: Observation of Divergent Reaction Mechanisms in the Palladium-Mediated Acetoxylation of Unsaturated Thioacetals

The Pd-mediated oxidation of unsaturated thioacetals gives either allyl or vinyl esters, depending on the substrate structure. We report the characterization of a range of sulfur-stabilized palladium intermediates via a combined computational and experimental NMR approach, demonstrating that the oxidation proceeds via two divergent reaction mechanisms. We were also able to synthesize an unusual sigma-bound Pd complex, via acetoxypalladation of an unsaturated dithiane, which was characterized by X-ray crystallography