Structure and regulation of the ALS gene

The mouse ALS gene spans at least 6 kb. It contains 2 exons which encode a protein highly homologous to human and rat ALS. It was localized to mouse chromosome 17 by fluorescent in situ hybridization. The 5′ flanking region lacks a TATA box but contains GC boxes that may be recognised by transcription factors such as Sp1. Hepatic ALS mRNA is decreased in rats following hypophysectomy, and restored by systemic treatment with recombinant human GH. In transient transfection assays, GH stimulated ALS promoter activity in a rat hepatoma cell line, but not in 3T3-F442A mouse preadipocyte fibroblasts, suggesting that utilisation of the ALS promoter is cell-type specific. The rat hepatoma system is a promising system to study the regulation of ALS gene expression, and the signalling pathways of CH regulation.