James E. Dahlberg
Honors & Awards
Research in my laboratory focuses on RNA biology. We have used several model systems, including bacteria, mammalian tissue culture cells and frogs to learn about the synthesis, transport and function of a variety of RNA molecules.
Our current focus, in collaberation with Elsebet Lund, is on the mechanism and control of microRNA processing, and the function of miRNAs during early development in Xenopus laevis oocytes and early embryos. MiRNAs are short (~22 nucleotides) molecules found in metazoans, which control the stability and function of messenger RNAs. We have shown that in early frog embryos miR-427 promotes the deadenylation and destabilization of certain maternally inherited mRNAs, preparing the embryo for a subsequent stage of development. This experimentally manipulatible system has allowed us to ask detailed questions about the assembly and function of RNPs that contain miRNA.
We recently showed that frog oocytes and early embryos are deficient in Ago proteins, resulting in non-specific inhibition of miRNA maturation by siRNAs. Also, the lack of Ago2 activity explains why these embryos cannot carry out RNAi. However, we have found that we can use this powerful targeted gene knock-out method by supplementing the system with exogenous human Ago2 protein; this discovery now allows us to investigate the roles of specific proteins early in development.
Publications of Note
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of Wisconsin - Department
of Biomolecular Chemistry