We have isolated the gene that encodes the neural-specific RNA binding
protein HuD in the mouse (Elavl4), and have mapped its location to th
e mid-distal region of chromosome 4, close to the neurological mutant
clasper. The coding region of the Elavl4 gene covers approximately 44
kb; the first two RNA binding domains (RBDs) that are homologous to th
e two RBDs found in the Drosophila sex-lethal gene are each encoded in
two exons, whereas the third RED is encoded in a single exon. Elavl4
mRNAs are alternatively spliced in the region between RBDs 2 and 3 due
to the variable use of two micro-exons, and RNase protection analysis
indicates that two of four possible splice variants are the predomina
nt isoforms expressed in the central nervous system. The high degree o
f sequence conservation between the Hu proteins suggests that the exon
organization of all the Hu protein genes will be similar, if not iden
tical, to the Elavl4 gene. (C) 1998 Elsevier Science B.V.