Structure and promoter analysis of the human unc-33-like phosphoprotein gene - E-box required for maximal expression in neuroblastoma and myoblasts

The human unc-33-like phosphoprotein (hUlip/ CRMP-4) is a member of a famil y of developmentally regulated genes that are highly expressed in the nervo us system. Mutations in the C. elegans unc-33 gene lead to worms with abnor mal movements. The hUlip gene encodes a 570-amino acid protein with 98% hom ology 60 its murine (Ulip) (Byk, T., Dobransky, T., Cifuentes-Diaz, C., and Sobel, A. (1996) J. Neurosci. 16, 688-701) and rat (CRMP-4) (Wang, L. H., and Strittmatter, S. M. (1996) J. Neurosci, 16, 6197-6207) counterparts (Ga etano, C., Matsuo, T., and Thiele, C. J. (1997) J.. Biol. Chem. 272, 12195- 12201). The hUlip gene was isolated from a human genomic library. It contai ns 15 exons, including an exon defined by an anaplastic oligodendroglioma e xpressed sequence tag, and spans at least 61.7 kilobases. hUlip lacks seque nces corresponding to the first six exons found in unc-33. unc-33 exons cor respond to homologous hUlip exons as follows: VII to 1 and 2, VIII to 3-9, IX to 10-12, and X to 13 and 14. Using the hUlip clone 1 phage, fluorescenc e in situ hybridization analysis indicates that the hybridization signal lo calizes to human chromosome 5q32. Deletion analysis of 5'-flanking sequence s delineated the sequences sufficient to express a reporter gene in both ne uroblastoma cells and myoblasts. A consensus MyoD/myogenin binding site is located in a region of the downstream promoter that is nearly identical to its mouse homologue. Mutagenesis shows that this conserved MyoD/myogenin si te is necessary for full promoter activity in both myoblasts and neuroblast oma cells.