Gene organization and chromosome location of the neural-specific RNA binding protein Elavl4.

We have isolated the gene that encodes the neural-specific RNA binding protein HuD in the mouse (Elavl4), and have mapped its location to the 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 the two RBDs found in the Drosophila sex-lethal gene are each encoded in two exons, whereas the third RBD 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 predominant isoforms expressed in the central nervous system. The high degree of sequence conservation between the Hu proteins suggests that the exon organization of all the Hu protein genes will be similar, if not identical, to the Elavl4 gene.