Enables guanine/thymine mispair binding activity. Acts upstream of or within maintenance of DNA repeat elements. Predicted to be part of MutSalpha complex. Predicted to be active in nucleus. Is expressed in several structures, including central nervous system; immature eye; neural tube; optic primordium; and ventral mesoderm. Human ortholog(s) of this gene implicated in Lynch syndrome; colorectal carcinoma; endometrial cancer; hereditary nonpolyposis colorectal cancer type 5; and mismatch repair cancer syndrome. Orthologous to human MSH6 (mutS homolog 6).