Abstract: Objective Investigation of the cis regulatory functional role of natural antisense transcript (NAT) in expression of same genome locus coding gene, Lmo4. Methods Rapid Amplification of cDNA Ends (RACE), RT-PCR, real time qRT-PCR, in situ and Luciferase reporter assay were employed to capture the full length of the NAT, to display the spatio-temporal patterns of coding gene and noncoding RNA in the development of embryonic brain, and to analyze the regulatory role of NAT in the expression of Lmo4, respectively. Results The results show that Lmo4as is a noncoding RNA transcript with a poly-A tail, and the full length sequence of this NAT transcript were cloned. Moreover, it was shown that Lmo4as function as a negative regulator on the expression of Lmo4 at the post-transcriptional level, similar with a microRNA functional role, miR-124. Conclusion The NAT Lmo4as function as a cis repressor on the coding gene Lmo4 at post-transcriptional level.

Key words: mouse brain development, Lmo4, natural antisense transcript, in situ, post-transcriptional regulation