DIFFERENTIAL EXPRESSION OF A PROTEASOMAL SUBUNIT DURING CHICK DEVELOPMENT

Removal of cardiac neural crest disrupts normal development of the hea rt and pharynx. Subtractive hybridization was used to identify differe ntially expressed messages after neural crest ablation in chick embryo s, A 1 kb clone, homologous to PROS-28, a 28 kD alpha subunit of a Dro sophila proteasome, was differentially expressed in embryos lacking ne ural crest. An increase of GPROS-28 expression in the head and pharyng eal arches of stages 12-21 chick embryos without cardiac neural crest accompanied generalized low-level expression throughout experimental a nd normal embryos. In addition, high levels of GPROS-28 expression wer e detected in normal embryos at particular sites and times in developm ent in the limb buds, mesonephros, heart, liver, neural tube, dorsal r oot ganglia, and lung buds, when the cells in these regions were under going intense proliferation. (C) 1997 Academic Press.