THE FIRST INTRON OF THE MOUSE NEUROFILAMENT LIGHT GENE (NF-L) INCREASES GENE-EXPRESSION

Neurofilament expression is developmentally and post-transcriptionally controlled. Using transient transfection assays in mouse L cells, we demonstrate that the expression of the mouse neurofilament light subun it (NF-L) is influenced by intron sequences. NF-L expression was decre ased twenty fold upon deletion of the three intron sequences. Elements contained principally within a 350 bp region of intron 1 were respons ible for enhanced NF-L expression. Enhancement of expression did not o ccur when intron I was placed 3' to a heterologous chloramphenicol ace tyl transferase (CAT) gene whose expression was driven by NF-L 5' sequ ences. The intron enhancement of NF-L expression was not promoter-spec ific and also occurred with the mouse sarcoma virus (MSV) LTR promoter . These data suggest intron sequences may be important in regulating N F gene expression.