Cloning and characterization of a Golgin-related gene from the large-scalepolymorphism linked to the PML gene

Megabase-scale mapping of the PML gene locus revealed the presence of a lar ge-scale insertion-deletion polymorphism located 25 kb downstream of the PM L gene. The polymorphism is organized as a head-to-tail tandem 25-kb repeat containing one to five units. Characterization of the first repeat unit do wnstream of PML revealed the presence of a gene with strong homology to a f amily of Golgin-related proteins. The gene, designated GLP (for Golgin link ed to PML), is strongly expressed as a 6-kb transcript in normal human test is, In situ hybridization of normal human testis demonstrated that the expr ession of GLP was restricted to late meiotic germ cells. There was weak exp ression in late pachytene spermatocytes and strong expression in spermatids , GLP is 50% homologous to other Golgin-related proteins including the vesi cle docking protein GM130. Southern blot hybridization of genomic DNA with a GLP probe demonstrated numerous homologous bands outside the PML locus. T hree of these loci have been mapped by fluorescence in situ hybridization t o chromosome loci 9q34.1, 15q11-q13, and 15q22-q24. Hybridization of a GLP cDNA probe to a zoo blot demonstrated multiple signals in nonhuman primates but not in other species and suggested the duplication of an ancestral loc us around 20 million years ago. (C) 2000 Academic Press.