Structural comparison of zebrafish Elav/Hu and their differential expressions during neurogenesis.

The present communication reports the isolation and characterization of three new zebrafish elav/Hu (Kim, C.-H., Ueshima, E., Muraoka, O., Tanaka, H., Yeo, S.-Y., Huh, T.-L. and Miki, N., Zebrafish elav/HuC homologue as a very early neuronal marker. Neurosci. Lett., 216 (1996) 109-112) homologues, HuA, HuD and HuG. While HuA and HuG showed weak and ubiquitous expressions, HuD, as well as HuC, were specifically expressed in the neuronal cells. The first expression of HuD was detectable of the 10-somite stage, that is, several hours later than HuC. After 24 h of embryonic development, although HuD and HuC expressions overlapped overall, the cells expressing HuD were restricted to subsets of the HuC-positive neuronal cells in the brain and spinal cord. These differentially regulated spatial and temporal expression patterns implied distinct roles for HuC and HuD in neuronal determination and neuronal differentiation, respectively.