This web page was produced as an assignment for an undergraduate course at Davidson College
My Favorite Yeast Genes
The gene YML085C or TUB1 is located chromosome XIII in Saccharomyces cerevisiae or Brewer's Yeast. This 1460 nucleotide gene encodes a 447 amino acid long protein, alpha tubulin (1).
Alpha tubulin, along with beta tubulin (encoded for by the gene TUB2) makes up microtubules, one of the most important structural proteins in all eukaryotes. A third gene, TUB3 encodes another version of alpha tubulin. TUB3 is only expressed at low levels and has not been shown to be essential for yeast survival (Richards et al., 2000). As in most other eukaryotes, Microtubules are necessary for chromosome movement in S. cerevisiae. In yeast, the only other cellular functions known to depend on microtubules are the movement of nuclei to the bud neck before mitosis and the fusion of nuclei after mating (Richards et al., 2000).
TUB1 appears to be an essential gene to S. cerevisae as a null mutant for TUB1 results in an inviable phenotype (1). Heterozygotes for this mutation slow growing and sporulate poorly (1).
As might be expected the TUB1 gene shows great sequence similarity (70%) to the human gene for alpha tubulin (1). This makes sense because human microtubules are similar to those in yeast and perform similar cellular functions .
LEE1: unannotated gene
All that is known about the gene YPL054W, also known as LEE1, is that it is a 906 base pair gene on S. cerevisae chromosome XVI (1) This gene is translated into a protein that is 301 amino acids long (1).
Predicted analysis of the role of LEE1 in yeast::
A BLAST of the neucleotide sequence revealed no other known genes that were very similar to LEE1
A BLAST of amino acid sequence revealed a "probable zinc finger protein" from Schizosaccharomyces pombe (another type of yeast commonly known as fission yeast) that showed a 50% amino acid sequence similarity to LEE1. This 50% similarity was confined to a continuous region in the center of LEE1. To me this suggests that these two genes may has similar functional domains that have been concerved across these two species of yeast. LEE1 may therefore also have zinc-finger domains and thus might play a role as a transcripton factor or other DNA binding protein. In addition, the fact that this protein is fairly small also supports this hypothesis.
A Conserved Domain search confirmed the presence of two zinc finger domains within the protein.
A Kyte-Doolittle hydropathy plot showed no peaks greater than 2. This suggests that this protein has no transmembrane region. This would be consistant with the function of this protein as a transcription factor or other DNA binding protein.
A PREDATOR search only showed that there are a few small regions of alpha helix (blue).
Web Recources Used:
Concerved Domain <http://www.ncbi.nlm.nih.gov/Structure/cdd/wrpsb.cgi>
(1) SGD <http://genome-www.stanford.edu/cgi-bin/SGD/search>
(2) Richards K.L., et al. 2000. Structure-function relationships in yeast tubulins. Mol Biol Cell. 11:1887-903.
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