Expression of a novel splice variant of in developing human fetal brains that is upregulated upon the differentiation of NT2 cells.

mutations are associated with X-linked idiopathic congenital nystagmus (ICN); however, the underlying mechanisms whereby mutations of lead to ICN remain unclear. In a previous study, the first splice variant () was cloned and identified, and was hypothesized to play a significant role in neuronal differentiation and development. The present study investigated a novel multiple exon-skipping mRNA splice variant of , termed _, which was detected in NT2 cells using northern blotting. The mRNA expression levels of _ in the developing human fetal brain were examined using reverse transcription polymerase chain reaction (PCR), while the expression levels in NT2 cells treated with retinoid acid (RA) or bone morphogenetic protein-2 were investigated using quantitative PCR. The results revealed that the expression of _ was spatially and temporally restricted in human fetal brain development, and was upregulated upon RA-induced neuronal differentiation of the NT2 cells. These results indicated that as a novel splice variant of , _ may play a role in neuronal development.