A Novel Long Non-coding RNA, Modulates Dendrite Density and Expression of in Zebrafish.

Kalirin, a key player in axonal development, nerve growth and synaptic re-modeling, is implicated in many pathological conditions like schizophrenia and autism-spectrum disorders. Alternative promoters and splicing lead to functionally distinct isoforms, but the post-transcriptional regulation of Kalirin has not been studied. Here, we report a novel non-coding RNA, which we name , arising from the first exon of kalirin a () in the antisense orientation in zebrafish. The and transcripts are barely detectable during early development, but steadily increase by 24 hours post-fertilization (hpf) as the brain develops. Over-expression of in the zebrafish embryo led to an increase in expression. The morphology of the neurons cultured from injected embryos had significantly fewer and shorter dendrites. Although has no apparent sequence homolog in mammals, based on gene synteny, we found a non-coding RNA arising from the 5' end of the human gene and expressed in the human neuronal cell line, SH-SY5Y. We propose that the zebrafish lncRNA maintains dendritic length and density through regulation of expression and this may have further implications in mammalian systems.