ABSTRACT
This article was migrated. The article was marked as recommended. Undergraduate medical education relies on a variety of small group learning formats to deliver the curriculum, support collaborative learning, encourage critical thinking, as well as the development of a number of professional, clinical and generic attributes. However, the SARS-CoV-2 (COVID-19) pandemic of 2020 reminded us that unanticipated circumstances may necessitate a rapid and abrupt switch to delivering medical education through alternative means, while still upholding teaching standards and meeting learning and graduate outcomes. For many medical schools, the pandemic resulted in small group teaching being moved to an online format. The experience of students and facilitators moving small group learning tutorials to online synchronous delivery forms the basis for a set of recommendations when considering the delivery of small group teaching remotely.
ABSTRACT
The nematode cuticle is a protective collagenous extracellular matrix that is modified, cross-linked, and processed by a number of key enzymes. This Ecdysozoan-specific structure is synthesized repeatedly and allows growth and development in a linked degradative and biosynthetic process known as molting. A targeted RNA interference screen using a cuticle collagen marker has been employed to identify components of the cuticle biosynthetic pathway. We have characterized an essential peroxidase, MoLT-7 (MLT-7), that is responsible for proper cuticle molting and re-synthesis. MLT-7 is an active, inhibitable peroxidase that is expressed in the cuticle-synthesizing hypodermis coincident with each larval molt. mlt-7 mutants show a range of body morphology defects, most notably molt, dumpy, and early larval stage arrest phenotypes that can all be complemented with a wild type copy of mlt-7. The cuticles of these mutants lacks di-tyrosine cross-links, becomes permeable to dye and accessible to tyrosine iodination, and have aberrant collagen protein expression patterns. Overexpression of MLT-7 causes mutant phenotypes further supporting its proposed enzymatic role. In combination with BLI-3, an H2O2-generating NADPH dual oxidase, MLT-7 is essential for post-embryonic development. Disruption of mlt-7, and particularly bli-3, via RNA interference also causes dramatic changes to the in vivo cross-linking patterns of the cuticle collagens DPY-13 and COL-12. This points toward a functionally cooperative relationship for these two hypodermally expressed proteins that is essential for collagen cross-linking and proper extracellular matrix formation.
Subject(s)
Caenorhabditis elegans Proteins/metabolism , Caenorhabditis elegans/embryology , Collagen/metabolism , Embryo, Nonmammalian/metabolism , Extracellular Matrix/metabolism , NADPH Oxidases/metabolism , Peroxidases/metabolism , Amino Acid Sequence , Animals , Animals, Genetically Modified , Cross-Linking Reagents/metabolism , Female , Gene Expression Regulation, Developmental , Male , Molecular Sequence Data , Mutation/genetics , Phenotype , RNA Interference , Recombinant Proteins/genetics , Recombinant Proteins/isolation & purification , Recombinant Proteins/metabolism , Sequence Homology, Amino AcidABSTRACT
Progression to an invasive, metastatic tumour requires the coordinated expression and function of a number of gene products, as well as their regulation in the context of invasion. The transcription factor AP-1 regulates expression of many of those genes necessary for implementation of the invasion programme. Two such gene products, CD44 and ezrin, are both upregulated in fibroblasts transformed by v-fos and are commonly implicated in cell motility and invasion. Here we report that CD44 and ezrin colocalise to membrane ruffles and microvilli of A431 cells after treatment with EGF. However, A431 cells expressing dominant-negative c-Jun (TAM67), and which as a consequence fail to invade in response to EGF, also fail to correctly localise CD44 and ezrin. CD44 and ezrin are both substrates for Protein Kinase C, and we show that their EGF-dependent colocalisation requires Protein Kinase C activity. Associated with TAM67 expression and disrupted CD44 and ezrin colocalisation is the increased expression and activation of the novel PKC theta isoform. Expression of PKC theta in A431 cells results in the inhibition of cell motility and disrupted localisation of CD44 and ezrin. We propose that AP-1 regulates the integrity of Protein Kinase C signalling and identifies PKC theta as a potential suppressor of the invasion programme.
