Homeobox gene repertoire in adult rat dorsal root ganglia

Homeobox genes encode transcription factors that play key roles in embryonic development of the nervous system. Dorsal root ganglia are part of the peripheral nervous system that arises from the neural crest. Several homeobox genes are known to play important roles in the development of neural crest and dorsal root ganglia. Some of these remain expressed in the adult dorsal root ganglia (DRG). In order to get more insight into the homeobox gene repertoire in adult rat DRG, we performed RT-PCR with degenerate primers and identified twenty-two homeobox genes. We found homeobox genes that were reported before in embryonic or adult DRG, as well as homeobox genes associated before with neural crest (derivatives). Some of the genes were not reported in relation to neural crest or DRG before. Two homeobox genes displayed sequence differences with their mouse counterparts, possibly being close homologues. The diversity of homeobox genes expressed in adult DRG suggests that gene regulatory events initiated during development remain operative in the mature DRG.