The structure and expression of neuron-specific enolase gene

Abstract

Neuron-specific (γγ) enolase (NSE) is an isozyme form of glycolytic enzyme, enolase. We isolated genomic clones for NSE and clarified NSE gene structures. The NSE gene spanned about 9 kb and consisted of twelve exons and eleven introns. Multiple transcriptional start points were identified by a combination of S1 nuclease mapping and primer extension analysis. In the 5'-flanking region we found a TATA-like sequence TCTATAGGC which was only partially homologous to the consensus sequence, but we did not find a CAAT box. The sequence in the immediate 5 ' -flanking region was of a relatively high G + C content and contained GC-box-like clusters that did not correspond to the typical GC box. In addition, we found seven classes of the repeated sequences. In the introns 1, 5 and 10 there were tandem repeats (GT) 33, (GT) 21 and (GT) 24, respectively. The 3 ' end contains a single polyadenylation site and an identifier sequence 2 kb downstream from the poly(A)-addition site. The in vitro cell-free transcription of the truncated genomic DNA fragment using HeLa cell extract showed that the transcription start points have been correctly identified and the putative promoter sequences appear to be functional.