Localization of surfactant protein synthesis in human lung by in situ hybridization.
In order to investigate the sites of synthesis of the pulmonary surfactant-associated proteins, we performed tissue in situ hybridization. We used frozen sections of human lung tissue and 35S-UTP-labeled cRNA probes to localize mRNAs for the 35 kDa surfactant-associated protein (PSP-A) and for the precursor of one of the hydrophobic, low molecular weight surfactant-associated proteins (PSP-B). We found that PSP-A mRNA is present only in the alveolar epithelial type II cells with alveolar macrophages, bronchiolar epithelium, and other cells of the interstitutium being negative. PSP-B mRNA is present in both alveolar type II cells and in some cells of the bronchiolar epithelium. Macrophages and other cells were negative. The data in this report demonstrate that: (1) type II pneumonocytes are capable of synthesizing both PSP-A and PSP-B, (2) some cells of the human bronchiolar epithelium contain PSP-B mRNA but not PSP-A, and (3) human alveolar macrophages do not synthesize either PSP-A or PSP-B.
Phelps
D S
DS
Department of Pediatrics, Harvard Medical School, Boston, Massachusetts.
Floros
J
J
D006801:Humans; D008168:Lung / Q000378:metabolism*; D009693:Nucleic Acid Hybridization; D011510:Proteolipids / Q000096:biosynthesis* / Q000145:classification / Q000235:genetics; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants / Q000096:biosynthesis* / Q000145:classification / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism
D011510:Proteolipids; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants; D012333:RNA, Messenger