Structure and organization of the gene encoding human pulmonary surfactant proteolipid SP-B.
Human pulmonary surfactant proteolipid SP-B arises by proteolytic processing of a 42,000-dalton precursor. The active proteolipid SP-B is one of two small hydrophobic proteins identified in surfactant that impart surface-active properties to surfactant phospholipids. We report the isolation and characterization of complete SP-B cDNA from a human lung cDNA library. The cDNA was used to isolate the gene encoding the SP-B precursor from a lambda EMBL3 library of human embryonic kidney DNA. The entire SP-B gene was sequenced and is approximately 9.5 kb long, with 11 exons and 10 introns including a large 823-nucleotide 3' untranslated exon. The sequence derived from the exons differs from the cDNA sequence at 3 positions out of 2001, only one of which is in the translated region. Direct RNA sequencing indicated that the 5' untranslated region is only 14 nucleotides long. A number of putative regulatory elements were found upstream of the SP-B gene, including a GC box and several putative cAMP and glucocorticoid receptor binding sites. Several Alu repeats and a region of potential Z-DNA formation were found in the introns. Southern blotting of human genomic DNA probed with SP-B cDNA indicated the presence of only one SP-B gene in the human genome, and the gene was localized to chromosome 2.
Pilot-Matias
T J
TJ
Corporate Molecular Biology, Abbott Laboratories, IL 60064.
Kister
S E
SE
Fox
J L
JL
Kropp
K
K
Glasser
S W
SW
Whitsett
J A
JA
D000595:Amino Acid Sequence; D001483:Base Sequence; D004247:DNA / Q000032:analysis / Q000302:isolation & purification*; D005796:Genes; D006801:Humans; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D011510:Proteolipids / Q000235:genetics*; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid
D011510:Proteolipids; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants; D004247:DNA