STAG3 Background Information Stromalins are a group of highly conserved proteins that are characterized
by the stromalin conservative domain. Stromal antigen 3 (STAG3) is a nuclear protein that is expressed specifically in germinal cells. STAG3 associates with the synaptonemal complex (SC) via immunolocalization. The SC is a meiotic protein structure that aids in the pairing of homologous chromosomes. In mammals, STAG3 associates with the SC and assists in sister chromatid cohesion, which keeps the homologous chromosomes appropriately aligned during the pachytene stage of prophase I. STAG3 appears to be located at the interchromatid domain during metaphase I, but is undetectable in ana-phase I or any of the later stages of meiosis. The human STAG3 gene maps to 7q22. There have been six additional STAG3-related genes mapped in humans. Two of these genes flank the chromosomal breakpoints associated with the Williams-Beuren syndrome (WBS), a microdeletion syndrome with varied clinical presentations.
