yeast as a model Flashcards
why is yeast a good model (3)
functional conservation across most eukaryotic species, its capability for testing functional complementation and the fact that 40% of single- gene determinants of heritable human disease have functional homologues in yeast
how was functional complementation used to test the capability of mouse cDNA
the signalling capacity of yeast invertase was removed. mouse cDNA fragments were then incorporated into the yeast genome to see if any of them restored function and therefore encoded a signalling peptide
the yeast cell cycle is similar to the human cell cycle. what are the additional benefits (4)
it is easy to visualise the stage of the cycle the cell is in, size correlates to the cell stage, whole cultures can be synchronised and some mutants may arrest all of the cells at the same stage
what is transcriptomics
the analysis of all of the genes expressed at any one time
what are the applications of transcriptomics in terms of what it can characterise (6)
it can characterise gene expression in the stress response, metabolic shift, response to mating pheromones, synexpression, translational regulation and the regulatory role of TFs
what are the limitations of transcriptomics
it only accounts for transcripts and not post- translational modification, rate of degradation etc. more useful information is in the metabolome
how can transcriptomics can be applied
it can help predict cellular responses to new drugs
what are biological mutagens and why are they good
transposons which move around the genome and cause mutations. they are good because they have a sequence and can therefore be traced
how does systematic gene deletion work
every gene of the 6000 yeast ORF genes are deleted one by one to determine each of their roles in the phenotype, and also which mutants were affected by different conditions
why are deleted genes tagged and flanked with primers
they are amplified by PCR to determine relative abundance
why was the concept of haploinsufficiency beneficial
it allowed identification genes of which provide essential function as without enough of the protein product the yeast would be unable to perform normal growth
what is synthetic lethality
two mutations together give a more severe, lethal phenotype which suggests the two genes have a role in a common step eg a protein complex
how were synthetic lethal mutants identified
by exploiting the lethality of 5-FOA proteins on cells expressing URA3 genes
how does the yeast two hybrid assay work
if two TF fragments interact then the two proteins they are bound to much also interact, allowing identification of interacting proteins
what are synthetic yeasts and how do they promote genetic diversity
yeasts with completely synthesised, streamlined genomes. they promote diversity due to LoxP sites between each gene which can be cleaved by Cre recombinase. this allows DNA recombination via the SCRaMbLE process
