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Team:Johns Hopkins-BAG/A New Standard
From 2009.igem.org
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tRNA genes have been as a documented source of genome instability in Saccharomyces cerevisiae v. 1.0. As a measure to combat genome instability, as well as examine the effects of a more rigidly constrained genome, the tRNA genes for Sc 2.0 are being relocated to a specialized chromosome, the tRNA array. This entirely synthetic chromosome thus far only consists of the tRNA genes from chromosomes III and IX of S. cerevisiae. The tRNA array of chromosomes III and IX of S. cerevisiae 2.0 consists of 17 tRNA genes; each gene consists of the coding region of the tRNA From S. cerevisiae and the upstream and downstream flanking regions from a close relative of S. cerevisiae, Ashbya gossypii. Use of the fusion tRNA genes was required to avoid incorporating the repetitive sequences often found upstream of tRNAs in S. cerevisiae, as another aspect of our redesign philosophy for Sc 2.0 is to minimize nonessential repetitive DNA. Each of the genes is a representation of the same gene found on chromosome III and IX with all duplicates removed. Between each tRNA gene is a rox recombination site that will allow for subsequent induced recombination within and limited to the tRNA chromosome, when the Dre recombinase is expressed at the whim of the investigator, so that the importance of order and relative copy numbers of tRNA genes on the tRNA array chromosome can be examined. Also it will be possible to detect deletions and more complex rearrangements of genes using this system and their phenotypic effect.
