| Description |
For eukaryotes, lifetimes of mRNA molecules are regulated in the cytoplasm by trans-acting factors such as RNA-binding proteins and microRNAs (miRNAs). These lifetimes vary from 7 to 150 min for Saccharomyces cerevisiae (baker’s yeast), and are correlated with biological functions in protein complexes. Using different transcription inhibitors, we developed a microarray-based protocol for profiling variations in stabilities, both generically and for testing mutants of trans-acting factors in post-transcriptional gene regulation. We present results from profiling mRNA lifetimes in yeast and review approaches to study the regulatory potential of 3’UTR RNA secondary structures by using computational methods.
Current projects at York University that extend this work will be discussed and include:
1) Diagnostic markers: Using profiling of expression signatures of miRNAs in kidney cancer, novel markers of high clinical transparency and biostatistical robustness are developed that allow subtype classification.
2) Transcriptional silencing: MiRNAs are hypothesized to play a role in heterochromatin formation. A related function is served by a category of short scanning RNAs (scnRNAs) in the genome rearrangement of Tetrahymena thermophila. We present our work and novel findings about Twi1p and other factors from the collaborative project of expression profiling Tetrahymena’s life cycle during vegetation and conjugation/ genome rearrangement.
3) Immunoinformatics: Somatic hypermutation (SHM) is a key step in the affinity
maturation of mammalian antibodies. Our current collaborative work elucidates
the mutation profile of IGHV3-23 in patients suffering from Common Variable ImmunoDeficiency (CVID). Evidence is presented that transient ssDNA formation during transcriptional unfolding is an important factor in SHM.
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