Objective: To clone and identify expression pattern of the novel LNX gene, and characterize its molecular mechanism in all grades of human gliomas.
Methods: From a fetal brain cDNA library, we isolated the novel human LNX gene. The expression pattern of LNX gene in 16 normal tissues was examined by MTC panel (Clontech). Microarray were adopted and hybridized with LNX probes to examine the expression of novel gene in gliomas. Northern hybridization was used for verifying expression of LNX gene in gliomas. Two-hybrid screen in yeast was used to identify human LNX interacting proteins. Pull-down assays and Co-immunoprecipitation were transfected in HEK293 cells according to the lipofectAMINE protocol.
Results: We isolated a 3.7 kb cDNA containing an open reading frame (ORF) of 1,899 bp and a putative 632 amino acids protein, which was located on 4q12. cDNA microarray showed LNX was down-regulated in all 18 glioma samples and it was testified by Northern-blot. The MTC panel showed a ubiquitous expression pattern which highly expressed in adult brain, kidney and pancreas, while weak expression in heart, lung, etc. The two-hybrid screen in yeast revealed that LNX interacted with SKIP (Ski interacting protein) via PDZ domains. The co-immunoprecipation suggested that LNX interacted with SKIP in HEK293 cells and could affect the subcellular localization of Numb, which indicated that LNX might function as a molecular anchor that localized Numb to the subcellular site of its interaction with Notch.
Conclusion: cDNA microarray technology is a powerful technique in screening and locking differentially expressed genes in gliomas, LNX was closely related to human gliomas and suggested playing an important role in gliomas by notch signal approach.