SETMAR
Histone-lysine N-methyltransferase SETMAR is an enzyme that in humans is encoded by the "SETMAR" gene. Function. SETMAR contains a SET domain that confers its histone methyltransferase activity, on Lys-4 and Lys-36 of Histone H3, both of which are specific tags for epigenetic activation. It has been identified as a repair protein as it mediates dimethylation at Lys-36 at double-strand break locations, a signal enhancing NHEJ repair. Anthropoid primates, including humans, have a version of the protein fused to a Mariner/Tc1 transposase. This fusion region provides the DNA-binding abilities for the protein as well as  some nuclease activity. The transposase activity is lost due to a D610N mutation, but the domain itself can still recognize the mariner repeat elements and introduce nicks in the DNA. Model organisms. Model organisms have been used in the study of SETMAR function. A conditional knockout mouse line, called "Setmar" was generated as part of the International Knockout Mouse Consortium program — a high-throughput mutagenesis project to generate and distribute animal models of disease to interested scientists. Note that the mouse ortholog is does not have the Tc1/mariner ("MAR") fusion; such a fusion is found only in anthropoid primates . Therefore, the knockout mouse is not for SETMAR but only the SET domain of this chimeric fusion protein. Male and female animals underwent a standardized phenotypic screen to determine the effects of deletion. Twenty five tests were carried out on mutant mice and two significant abnormalities were observed. Homozygous mutant animals of both sex had abnormal retinal pigmentation and morphology, while males also had atypical peripheral blood lymphocyte parameters.