RBFOX2 is required for establishing RNA regulatory networks essential for heart development

Human genetic studies identified a strong association between loss of function mutations in RBFOX2 and hypoplastic left heart syndrome (HLHS). There are currently no Rbfox2 mouse models that recapitulate HLHS. Therefore, it is still unknown how RBFOX2 as an RNA binding protein contributes to heart development. To address this, we conditionally deleted Rbfox2 in embryonic mouse hearts and found profound defects in cardiac chamber and yolk sac vasculature formation. Importantly, our Rbfox2 conditional knockout mouse model recapitulated several molecular and phenotypic features of HLHS. To determine the molecular drivers of these cardiac defects, we performed RNA-sequencing in Rbfox2 mutant hearts and identified dysregulated alternative splicing (AS) networks that affect cell adhesion to extracellular matrix (ECM) mediated by Rho GTPases. We identified two Rho GTPase cycling genes as targets of RBFOX2. Modulating AS of these two genes using antisense oligos led to cell cycle and cell-ECM adhesion defects. Consistently, Rbfox2 mutant hearts displayed cell cycle defects and inability to undergo endocardial-mesenchymal transition, processes dependent on cell-ECM adhesion and that are seen in HLHS. Overall, our work not only revealed that loss of Rbfox2 leads to heart development defects resembling HLHS, but also identified RBFOX2-regulated AS networks that influence cell-ECM communication vital for heart development.

Use of World Wide Web server and browser software to support a first-year medical physiology course

We describe the use of a World Wide Web (Web) server to support a team-taught physiology course for first-year medical students. Our objectives were to reduce the number of formal lecture hours and enhance student enthusiasm by using more multimedia materials and creating opportunities for interactive learning. On-line course materials, consisting of administrative documents, lecture notes, animations, digital movies, practice tests, and grade reports, were placed on a departmental computer with an Internet connection. Students used Web browsers to access on-line materials from a variety of computing platforms on campus, at home, and at remote sites. To assess use of the materials and their effectiveness, we analyzed 1) log files from the server, and 2) the results of a written course evaluation completed by all students. Lecture notes and practice tests were the most-used documents. The students' evaluations indicated that computer use in class made the lecture material more interesting, while the on-line documents helped reinforce lecture materials and the textbook. We conclude that the effectiveness of on-line materials depends on several different factors, including 1) the number of instructors that provide materials; 2) the quantity of other materials handed out; 3) the degree to which computer use is demonstrated in class and integrated into lectures; and 4) the ease with which students can access the materials. Finally, we propose that additional implementation of Internet-based resources beyond what we have described would further enhance a physiology course for first-year medical students.