Pre-B-Cell Leukemia Homeobox Protein 4 (PBX4)

PBX4 encodes a homeodomain protein with similarity to a transcription factor involved in translocations in pre-B-cell leukemias. The presence of a homeobox domain suggests that this protein acts as a transcription factor, but this function has not been demonstrated.

Pbx4 was expressed in mouse prepubertal testis at around postnatal day 14, when the first spermatocytes had reached the pachytene stage of the meiotic prophase. In situ hybridization of adult mouse testis detected expression in all tubules in a ring of cells several layers thick in a region corresponding to meiotic spermatocytes. Immunostaining detected Pbx4 within the XY bodies of pachytene spermatocytes.