Protein phosphatase type-2A ( @entity4333 ) is a highly conserved @entity563 / @entity1889 phosphatase known to play a key role in cell proliferation and differentiation in vitro, but the role of @entity4333 in @entity1 embryogenesis remains unexplored. No particular information exists as to the tissue or cell specific expression of @entity4333 or the relevance of @entity4333 expression to @entity1 development in vivo. To examine expression of @entity4333 during @entity1 lung development, we studied fetal @entity35 from day 14 of gestation (the lung bud is formed on day 12 of gestation) to parturition. Western analysis with a specific @entity4333 catalytic subunit antibody identified a single 36 kDa protein, with protein levels two-fold higher in the 17 and 19 day embryonic lung as compared to the adult. With in situ hybridization and immunohistochemistry, both mRNA and protein for @entity4333 were localized equally to the epithelial lining of the embryonic lung airway and the surrounding mesenchyme in the 14 day embryonic lung. With maturation of the lung, @entity4333 becomes highly expressed in respiratory epithelium. The highest level of expression was in the earliest developing airways with columnar epithelium (the pseudoglandular stage, 15-18 days of gestation). There was a decrease in expression with the transformation to cuboidal epithelium by day 20 of gestation. This was most noticeable in the developing bronchial epithelium of the 19 and 20 day gestation lungs where only an occasional cell continues to express @entity4333 . Mesenchymal hybridization was most obvious in early endothelial cells of forming vascular channels at 17-19 days of gestation. @entity4333 respiratory epithelial expression mimicked the centrifugal development of the respiratory tree where the highest expression was in the peripheral columnar epithelium (15-18 days gestation) with only an occasional central bronchiolar cell continuing to express @entity4333 at 19 and 20 days gestation. Endothelial hybridization decreased with muscularization of large pulmonary arteries with low levels of expression detected in bronchial or vascular smooth muscle. In the newborn lung @entity4333 expression was decreased, but detectable in alveolar epithelium and vascular endothelium. In summary; 1) @entity4333 mRNA and protein exhibit cell specific expression during @entity35 lung development; 2) @entity4333 is highly expressed in the respiratory epithelium of the fetal @entity35 lung and is temporally related to the maturation of the bronchial epithelium; 3) and the @entity4333 subunit is highly expressed in early vascular endothelium, but not smooth muscle of the @entity35 lung.

Developmental expression and localization of the catalytic subunit of protein phosphatase 2A in XXXX lung.

@entity1 :: ('9606', 'Species') :: ['mammalian'] @entity563 :: ('CHEBI:17822', 'Chemical') :: ['serine'] @entity35 :: ('10116', 'Species') :: ['rat', 'rats'] @entity1889 :: ('CHEBI:26986', 'Chemical') :: ['threonine'] @entity4333 :: ('5524', 'Gene') :: ['PP2A']
@entity35 :: (10116,Species) :: ['rat']
