Natural antisense ribonucleic acids (RNAs) are transcribed from a large number of genes in various species, including humans and mice. The expression of neural cell adhesion molecule 1 (Ncam1) antisense non-coding RNAs (ncRNAs) in mice has been demonstrated by functional annotation of the mammalian genome project, but the localization of Ncam1 antisense ncRNAs has not been reported in mice tissues. In the present study, the localization of Ncam1 antisense ncRNAs was examined in tissues at several developmental stages by in situ hybridization. At days 14 and 17 of embryonic development, Ncam1 antisense ncRNAs were found in the heart, liver, lung, kidney, thymus and nerve regions including the brain (cerebral cortex, olfactory bulb, hippocampus and cerebellum) and spinal cord. In newborn mice, Ncam1 antisense ncRNAs were detected in the brain, kidney and thymus, but was not detected in other tissues. In 8-week-old mice, Ncam1 antisense ncRNAs were detected in the lung, kidney, thymus, pancreas, cornea, stomach and nerve regions including the brain. These results indicate that Ncam1 antisense ncRNAs are expressed in mice tissues. Notably, Ncam1 messenger RNAs (mRNAs), antisense ncRNAs co-localized in the Purkinje cells of the cerebellum and the levels of antisense ncRNAs appeared to be higher than those of mRNAs, suggesting that Ncam1 antisense ncRNAs may regulate the expression of Ncam1 mRNAs in the same cells.
Keywords: Purkinje cell; embryo; in situ hybridization; natural antisense non-coding RNAs; neural cell adhesion molecule 1.