The Shg1 subunit is one of the eight subunits of the COMPASS complex, complex associated with SET1, conserved in yeasts and in other eukaryotes up to humans. It is associated with the region of the Set1 protein that is N-terminal to the C-terminus, ie Set1-560-900. The function of Shg1 seems to be to slightly inhibit histone 3 lysine 4 (H3K4) di- and tri-methylation, and it is a pioneer protein. The COMPASS complex functions to methylate the fourth lysine of Histone 3 and for silencing of genes close to the telomeres of chromosomes [3].

1: The Saccharomyces cerevisiae Set1 complex includes an Ash2 homologue and methylates histone 3 lysine 4. Roguev A, Schaft D, Shevchenko A, Pijnappel WW, Wilm M, Aasland R, Stewart AF; EMBO J 2001;20:7137-7148. PMID:11742990

2: Protein interactions within the Set1 complex and their roles in the regulation of histone 3 lysine 4 methylation. Dehe PM, Dichtl B, Schaft D, Roguev A, Pamblanco M, Lebrun R, Rodriguez-Gil A, Mkandawire M, Landsberg K, Shevchenko A, Shevchenko A, Rosaleny LE, Tordera V, Chavez S, Stewart AF, Geli V; J Biol Chem. 2006;281:35404-35412. PMID:16921172

3: COMPASS, a histone H3 (Lysine 4) methyltransferase required for telomeric silencing of gene expression. Krogan NJ, Dover J, Khorrami S, Greenblatt JF, Schneider J, Johnston M, Shilatifard A; J Biol Chem. 2002;277:10753-10755. PMID:11805083