Functional Analysis Of Promoter Region In Human NEUREXIN1β Gene Of Autisim

Objective To chracterize human NRXN1β gene minimal promoter and identify the functional regions and cis-acting element for the transcriptional regulation of human NRXN1β gene.Methods First, to find the minimal promoter and the functional regions, we constructed a series of NRXN1β gene reporter plasmids with different promoter sizes and then evaluated the transcription activity using Dual Luciferase Reporter (DLR) assay. Second, We constructed a series of plasmids which have different mutantations in functional regions and that nearby, and evaluated the transcription activity using DLR assay to analyze the function of the nucleotides in the region. Third, we investigated the transcription factor binding sites in functional region with PROMO online program.Results After successfully constructing constructed a series of NRXN1β promoter luciferase report plasmids containing different size and mutant fragment, we found out two positive functional regions (-88/-73 and+149/+156) by comparing the differences between p4NRXN1β-88/+668 (9.63±1.46)、p4NRXN1β-73/+668 (2.08±0.51)、 p4NRXN1β-106/+156 (27.07±3.90) and p4NRXN 1(3-106/+149 (4.99±0.79), and another negative funtional region (+229/+419) by comparing p4NRXN1β-106/+229 (25.20±4.67) and p4NRXN1β-106/+419 (12.53±1.51).So the minimal or core promoter of human NRXN1β gene is likely to be the region of -88/+156. Second, our results have shown that the luciferase activities of the mutant plasmids in -84/-63 is lower than that of p4NRXN 1β-116/+156 significantly. However, there is no significant difference in luciferase activity between p4NRXN1β-116/+156-88-87M、 p4NRXN1β-116/+156-86-85M and p4NRXN1β-116/+156. So the functional region of -88/-73 is -84/-63. Third, two putative transcription factor binding sites (ABF1 and DBP) in -84/-63 have been identified with PROMO online program and those cis-acting elements may be responsible for high transcriptional activity of NRXN1β gene minimal promoter region NRXN1β-88/+156.Conclusions The minimal promoter of NRXN1β gene is NRXN1β-88/ +156. There are two positive functional regions-88/-73 and+156/+149, and one negative region +229/+419.The fuctional region-84/-63 may contain two transcription factor binding sites.