ZEBRAFISH ELAV HUC HOMOLOG AS A VERY EARLY NEURONAL MARKER/

Drosophila ELAV, a neuron-specific RNA binding protein, is expressed i n all neurons right after their birth. This specific pattern of expres sion has led to its use as a pan-neuronal marker. At least three membe rs of the elav family, HuD, HuC/ple21 and Hel-N1, have been reported t o be neuron-specific in vertebrates, although it is unknown which memb er of this family is expressed at the time of early neuronal determina tion. We have isolated a zebrafish elav/HuC homologue (zHuC) which has 89% homology to human HuC protein. It is first expressed in the neuro nal precursor cells in the neural plate immediately after gastrulation , and then high expression levels persist in most regions of the nervo us system. HuC, like elav in Drosophila, may be one of the earliest ne uronal markers in zebrafish.