RESUMO
Transfer RNAs (tRNAs) are transcribed as precursor molecules that undergo several maturation steps before becoming functional for protein synthesis. One such processing mechanism is the enzyme-catalysed splicing of intron-containing pre-tRNAs. Eukaryotic tRNA splicing is an essential process since intron-containing tRNAs cannot fulfil their canonical function at the ribosome. Splicing of pre-tRNAs occurs in two steps: The introns are first excised by a tRNA-splicing endonuclease and the exons are subsequently sealed by an RNA ligase. An intriguing complexity has emerged from newly identified tRNA splicing factors and their interplay with other RNA processing pathways during the past few years. This review summarises our current understanding of eukaryotic tRNA splicing and the underlying enzyme machinery. We highlight recent structural advances and how they have shaped our mechanistic understanding of tRNA splicing in eukaryotic cells. A special focus lies on biochemically distinct strategies for exon-exon ligation in fungi versus metazoans.
Assuntos
Células Eucarióticas , Objetivos , Células Eucarióticas/metabolismo , Íntrons , Precursores de RNA/química , Precursores de RNA/genética , Precursores de RNA/metabolismo , Splicing de RNA/genética , RNA de Transferência/genética , RNA de Transferência/metabolismo , Saccharomyces cerevisiae/metabolismoRESUMO
AIM: The purpose of this article is to inform nurse educators of an innovative and transformative approach to advancing nursing education through the creation of the Minnesota Alliance for Nursing Education (MANE). BACKGROUND: MANE was formed to answer national appeals to transform nursing education and demands by health care organizations for a more highly educated nursing workforce. METHOD: An action plan was developed with the Minnesota Action Coalition to create a dual admission community college and university eight-semester baccalaureate curriculum that students could complete seamlessly in four years. RESULTS: Admissions to the program have been robust, matriculation rates to upper division course work have exceeded initial goals, and diversity of students is increasing. CONCLUSION: Measures to date show that MANE is a viable and successful program that is surpassing its initial goals.
Assuntos
Bacharelado em Enfermagem , Pesquisa em Educação em Enfermagem , Currículo , Educação em Enfermagem , Humanos , Minnesota , Estudantes de EnfermagemRESUMO
Acinar cells require a functional apical actin web for secretion. During stimulation with supraphysiological concentrations of cholecystokinin (CCK), a condition that mimics acute pancreatitis, the actin filaments disintegrate. This leads to retention of secretory enzymes and, together with their premature activation, results in cell injury. Actin filaments are anchored through membrane-associated protein complexes that can be regulated through Src-family kinases in some model systems. Here we show that the Src-family kinases Yes and Lyn, but not Src and Fyn, are expressed in isolated pancreatic acini of Wistar rats. Upon stimulation with supramaximal secretory CCK (10(-8) M), Yes became reversibly tyrosine-phosphorylated and activated within 2 min. Immunocytochemical and subcellular fractionation studies showed reversible redistribution of Yes to the apical actin web and to the membrane fraction within 5 min. Coimmunoprecipitation demonstrated that Yes forms a complex with the focal adhesion protein Pyk2, which increased with CCK stimulation. In functional studies, inhibition of Src-kinase activity with PP2 partially reversed actin disintegration and also restored amylase secretion. We conclude that Yes participates in the regulation of the acinar cell actin, probably by interaction with Pyk2.