It was first identified in yeast as a gene involved in mating type switching [20], but is now known to be a highly conserved gene in organisms ranging from archea to humans [21].
Correct regulation of heterochromatin silencing is essential for efficient mating type switching.
Furthermore, Mec1 is known to activate the SCF/UFO1 complex to degrade HO, an endonuclease involved in mating type switching.
Homozygous diploid strains of the WT and UBP7 mutant were created by mating type switching using the YCp50::HO plasmid [ 92] and mating haploid strains of opposite mating type.
Additionally, transcription factors MATα1 and MATα2, the yeast mating type loci, contain an SCD and bind SCD-containing Mcm1, further suggesting additional targets for Tel1/Mec1 during mating type switching.
Those include genes involved in mating type switching (for instance, swi1, swi5, swi6, and swi10) and genes in the pheromone-activated MAPK signaling pathway (e.g., bry1 and bry2).
Many Puf proteins have been identified as essential factors for several aspects of development such as germline stem cell maintenance, synaptic plasticity, embryonic axis patterning, and mating type switching [ 13- 17].
This is important in many cellular contexts including neuronal dendrites (Kindler and Kreienkamp, 2012), oocytes and early embryos (Lasko, 2009), and even in single-celled eukaryotes, such as the budding yeast, where controls over ASH1 mRNA localization and translation establish the specificity of mating type switching (Paquin and Chartrand, 2008).
However, although the P-factor-specific protease Sxa2 lowers the amount of P-factor pheromone and thus lowers the effects on M cells, mating type switching ensures equal distributions of cells with mating types P and M. The model so far assumes all cells as well as each secreted pheromone molecule residing in the same solution, i.e. there is no distinction between different locations.
