Genomic structure and expression of parathyroid hormone-related protein gene (PTHrP) in a teleost, Fugu rubripes

In this study we describe the isolation and characterisation of the parathy roid hormone-related protein (PTHrP) gene from the teleost Fugu rubripes. T he gene has a relatively simple structure, compared with tetrapod PTHrP gen es, composed of three exons and two introns, encompassing 2.25 kb of genomi c DNA. The gene encodes a protein of 163 amino acids, with a putative signa l peptide of 37 amino acids and a mature peptide of 126 amino acids. The ov erall homology with known tetrapod PTHrP proteins is low (36%), with a nove l sequence inserted between positions 38 and 65, the absence of the conserv ed pentapeptide (TRSAW) and shortened C-terminal domain. The N-terminus sho ws greater conservation (62%), suggesting that it may have a hypercalcaemic function similar to that of tetrapod PTHrP. In situ localisation and RT-PC R have demonstrated the presence of PTHrP in a wide range of tissues with v arying levels of expression. Sequence scanning of overlapping cosmids has i dentified three additional genes, TMPO, LDHB and KCNA1, which map to human chromosome 12, with the latter two mapping to 12p12-11.2. PTHrP in human al so maps to this chromosome 12 sub-region, thus demonstrating conservation o f synteny between human and Fugu. (C) 2000 Elsevier Science B.V. All rights reserved.