Enables identical protein binding activity. Acts upstream of or within negative regulation of transcription, DNA-templated. Located in chromocenter; pericentric heterochromatin; and pronucleus. Is expressed in several structures, including alimentary system; genitourinary system; integumental system; nervous system; and sensory organ. Orthologous to human CBX1 (chromobox 1). [provided by Alliance of Genome Resources, Apr 2022]