Bone morphogenetic protein 7 increases chick photoreceptor outer segment initiation.

Purpose: The purpose of this study was to investigate the regulation of photoreceptor differentiation and outer segment elongation by the growth factor BMP7.

Methods: Dissociated low-density embryonic day 6 (E6) chick retinal cultures were grown for 6 days in the presence of BMP7, other members of the TGF-beta family of growth factors, or control vehicle. Cultured cells were characterized using microscopy, immunocytochemistry, and RT-PCR.