RRM
2008 Rustbelt RNA Meeting
RRM
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Poster abstracts
Abstract:
tRNAs are small RNA molecules that function in delivering amino acids to the ribosome during translation. We are studying how tRNA moves from its site of synthesis in the nucleus to its site of function in the cytoplasm. The yeast tRNA β-importin member, Los1, binds to end-processed tRNAs in the nucleus and exports them to the cytoplasm. However, since Los1 is unessential, additional nuclear export tRNA pathways must exist. Our lab identified another β-importin, Msn5, that functions in re-export of previously cytoplamsic tRNAs from the nucleus to the cytoplasm. Furthermore, we have shown that a temperature sensitive mutation of a third essential β-importin, Crm1, causes tRNA nuclear accumulation.
The question is: are Los1, Msn5, and Crm1 the only proteins involved in tRNA nuclear export? To study this, I am constructing yeast strains bearing multiple mutations of the known genes. Should the crm1-1 msn5Δ los1Δ triple mutant be viable, it will suggest there are other unidentified tRNA nuclear pathways. However, if the triple mutant is inviable, then possibly Los1, Msn5, and Crm1 are the only exportins involved. Previously, the los1Δ msn5Δ double deletion and the crm1-1 los1Δ double mutant were determined to be viable. I have constructed the crm1-1 msn5Δ::NAT double mutant and learned that it is also viable. However, interestingly, it displays increased temperature sensitivity compared with either single mutant. Therefore, the presence of these two mutations likely further impairs the export of tRNA from the nucleus. As this double mutant is viable, I am constructing the triple crm1-1 msn5 los1 mutant.
References:
Hopper, A.K. et al. (2008) A decade of surprises for tRNA nuclear-cytoplasmic dynamics. Trends Cell Biol. 18(3), 98-104.
Keywords: tRNA, export
