Silencing motifs in the Clr2 protein from fission yeast, Schizosaccharomyces pombe.

The fission yeast, Schizosaccharomyces pombe, is a well-established model for heterochromatin formation, but the exact sequence of events for initiation remains to be elucidated. The essential factors involved include RNA transcribed from repeated sequences together with the methyltransferase Clr4. In addition, histone deacetylases, like Clr3, found in the SHREC complex are also necessary for transcriptional silencing.

Hydrogenosomes in the diplomonad Spironucleus salmonicida.

Acquisition of the mitochondrion is a key event in the evolution of the eukaryotic cell, but diversification of the organelle has occurred during eukaryotic evolution. One example of such mitochondria-related organelles (MROs) are hydrogenosomes, which produce ATP by substrate-level phosphorylation with hydrogen as a byproduct. The diplomonad parasite Giardia intestinalis harbours mitosomes, another type of MRO.