DIFFERENTIAL EXPRESSION OF RAR-BETA AND RXR-GAMMA TRANSCRIPTS IN CULTURED CRANIAL NEURAL CREST CELLS

In situ hybridization reveals that RAR-beta and RXR-gamma genes in mesencephalic neural crest cultures are independently regulated. RAR-beta transcripts are found in all cells, with a slight increase in signal/cell with time in culture. In contrast, the distribution of RXR-gamma transcript is initially uniform but becomes increasingly heterogeneous, so that after 72 h in culture, a significant proportion of cells lack transcripts while a small subpopulation contains very high levels of message. These differences in the behaviour of the RAR beta and RXR gamma genes in vitro can be related to differences in their expression patterns in vivo.