Other Publications (1)
Articles by Susanne Blaser Imboden in JoVE
Horizontal Gel Electrophoresis for Enhanced Detection of Protein-RNA Complexes Megan E. Dowdle1, Susanne Blaser Imboden1, Sookhee Park1, Sean P. Ryder2, Michael D. Sheets1 1Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, 2Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School Native polyacrylamide gel electrophoresis is a fundamental tool for analyzing RNA-protein interactions. Traditionally most experiments have used vertical gels. However, horizontal gels provide several advantages, such as the opportunity to monitor complexes during electrophoresis. We provide a detailed protocol for generating and using horizontal native gel electrophoresis.
Other articles by Susanne Blaser Imboden on PubMed
Limiting Ago Protein Restricts RNAi and MicroRNA Biogenesis During Early Development in Xenopus Laevis Genes & Development. Jun, 2011 | Pubmed ID: 21576259 We show that, in Xenopus laevis oocytes and early embryos, double-stranded exogenous siRNAs cannot function as microRNA (miRNA) mimics in either deadenylation or guided mRNA cleavage (RNAi). Instead, siRNAs saturate and inactivate maternal Argonaute (Ago) proteins, which are present in low amounts but are needed for Dicer processing of pre-miRNAs at the midblastula transition (MBT). Consequently, siRNAs impair accumulation of newly made miRNAs, such as the abundant embryonic pre-miR-427, but inhibition dissipates upon synthesis of zygotic Ago proteins after MBT. These effects of siRNAs, which are independent of sequence, result in morphological defects at later stages of development. The expression of any of several exogenous human Ago proteins, including catalytically inactive Ago2 (Ago2mut), can overcome the siRNA-mediated inhibition of miR-427 biogenesis and function. However, expression of wild-type, catalytically active hAgo2 is required to elicit RNAi in both early embryos and oocytes using either siRNA or endogenous miRNAs as guides. The lack of endogenous Ago2 endonuclease activity explains why these cells normally are unable to support RNAi. Expression of catalytically active exogenous Ago2, which appears not to perturb normal Xenopus embryonic development, can now be exploited for RNAi in this vertebrate model organism.