title: Organization of the human SP-A and SP-D loci at 10q22-q23. Physical and radiation hybrid mapping reveal gene order and orientation.
abstract: The human surfactant protein (SP) A locus has been assigned to chromosome 10q22-q23 and consists of two very similar genes, SP-A1 and SP-A2, as well as a truncated pseudogene. SP-A belongs to the family of collagenous C-type lectins along with mannose binding protein (MBP) and SP-D, both of which have also been mapped to the long arm of chromosome 10. In this article we report the relative location and orientation of each of the SP-A and SP-D genomic sequences. Characterization of two overlapping genomic clones revealed that the SP-A pseudogene lies in a reverse orientation 15 kb away from the 5' side of SP-A1. This finding was verified by the amplification of the entire SP-A pseudogene/SP-A1 intergenic region using long-range polymerase chain reaction. The relative location of SP-A2 and SP-D was then ascertained by testing a number of sequence tagged sites against the Stanford TNG3 and G3 radiation hybrid panels. The radiation hybrid mapping data showed that both SP-A2 and SP-D are on the 5' side of SP-A1 at approximate distances of 40 kb and 120 kb, respectively. The SP-A and SP-D loci were also oriented relative to the centromere, with the overall order being: centromere-SP-D-SP-A2-pseudogene-SP-A1- telomere.
authors.affiliation: Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033, USA.
authors.forename: R R
authors.initials: RR
authors.lastname: Hoover
authors.forename: J
authors.initials: J
authors.lastname: Floros
mesh_terms: D002503:Centromere; D002874:Chromosome Mapping / Q000379:methods; D002879:Chromosomes, Human, Pair 10; D003001:Cloning, Molecular; D015698:Genomic Library; D006023:Glycoproteins / Q000235:genetics*; D006801:Humans; D016133:Polymerase Chain Reaction; D011510:Proteolipids / Q000235:genetics*; D011544:Pseudogenes; D037662:Pulmonary Surfactant-Associated Protein A; D037663:Pulmonary Surfactant-Associated Protein D; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants / Q000235:genetics*; D017422:Sequence Analysis, DNA
chemical_list: D006023:Glycoproteins; D011510:Proteolipids; D037662:Pulmonary Surfactant-Associated Protein A; D037663:Pulmonary Surfactant-Associated Protein D; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants; C445842:SFTPA1 protein, human; C445843:SFTPA2 protein, human