ENO3

Enolase 3 (ENO3), more commonly known as beta-enolase (ENO-β), is an enzyme that in humans is encoded by the ENO3 gene.

This gene encodes one of the three enolase isoenzymes found in mammals. This isoenzyme is found in skeletal muscle cells in the adult where it may play a role in muscle development and regeneration. A switch from alpha enolase to beta enolase occurs in muscle tissue during development in rodents. Mutations in this gene have be associated glycogen storage disease. Alternatively spliced transcript variants encoding different isoforms have been described.[provided by RefSeq, Jul 2010]

Structure

ENO3 is one of three enolase isoforms, the other two being ENO1 (ENO-α) and ENO2 (ENO-γ). Each isoform is a protein subunit that can form hetero- or homodimers of the following combinations: αα, αβ, αγ, ββ, and γγ.

Gene

The ENO3 gene spans 6 kb and contains 12 exons, though the first exon is an untranslated region and, thus, non-coding. This first intron, along with the 5'-flanking region, contains a consensus sequence for muscle-specific regulatory factors that includes a CC(A + T-rich)6GG box, a M-CAT-box CAATCCT, and two myocyte-specific enhancer-binding factor 1 boxes. Upstream of the first exon lies a TATA-like box and CpG-rich region, which contains recognition motifs for binding transcriptional regulatory factors such as Sp1, activator protein 1 and 2, CCAAT box transcription factor/nuclear factor I, and cyclic AMP. Unlike the other enolase genes, which possess multiple transcription initiation sites, ENO3 possesses a single initiation site located 26 bp downstream of the TATA-like box.