Zeng X, Yutzey K E, Whitsett J A
Children's Hospital Medical Center, Division of Pulmonary Biology and Neonatology, Cincinnati, Ohio, USA.
J Anat. 1998 Oct;193 ( Pt 3)(Pt 3):399-408. doi: 10.1046/j.1469-7580.1998.19330399.x.
Expression of surfactant proteins SP-A, SP-B and the transcription factors TTF-1 and HNF-3beta was identified by immunohistochemistry in the developing chicken. SP-B, a small hydrophobic peptide critical for lung function and surfactant homeostasis in mammals, was detected in the epithelial cells of parabronchi in embryonic chicken lung from the 15th day of incubation, prior to the onset of the breathing movements and was expressed at high levels in the posthatching chicken lung. SP-A, an abundant surfactant protein involved in innate defence of the mammalian lung, was detected in the chick embryo in subsets of epithelial cells in the mesobronchus, starting from d 15 and was detected in the posthatching chicken lung. The transcription factors hepatocyte nuclear factor 3beta (HNF-3beta) and thyroid transcription factor-1 (TTF-1), both regulators epithelial cell differentiation and gene expression in mammalian species, were detected at the onset of lung bud formation (d 4 of incubation) and throughout lung development. Abundant nuclear expression was detected in nuclei of respiratory epithelial cells of developing bronchial tubules for both transcription factors. In contrast to the surfactant proteins, expression of both TTF-1 and HNF-3beta decreased markedly in posthatching chicken lung. The expression of SP-A and SP-B in chick lung demonstrates the conservation of surfactant proteins in vertebrates. The temporospatial pattern of TTF-1 and HNF-3beta overlaps with that of SP-A and SP-B, supporting their potential roles in chick lung development and demonstrating the conservation of regulatory mechanisms contributing to gene expression in respiratory epithelial cells in vertebrates.
通过免疫组织化学法在发育中的鸡体内鉴定了表面活性蛋白SP-A、SP-B以及转录因子TTF-1和HNF-3β的表达。SP-B是一种对哺乳动物肺功能和表面活性物质稳态至关重要的小疏水肽，在孵化第15天的鸡胚肺中，在呼吸运动开始之前，就已在副支气管的上皮细胞中检测到，并且在出壳后鸡肺中高表达。SP-A是一种在哺乳动物肺先天防御中起作用的丰富表面活性蛋白，从第15天开始在鸡胚中主支气管的部分上皮细胞中检测到，并且在出壳后鸡肺中也能检测到。转录因子肝细胞核因子3β（HNF-3β）和甲状腺转录因子-1（TTF-1），在哺乳动物中都是上皮细胞分化和基因表达的调节因子，在肺芽形成开始时（孵化第4天）以及整个肺发育过程中都能检测到。在发育中的细支气管呼吸上皮细胞核中，这两种转录因子都检测到丰富的核表达。与表面活性蛋白不同，TTF-1和HNF-3β在出壳后鸡肺中的表达均显著下降。SP-A和SP-B在鸡肺中的表达表明表面活性蛋白在脊椎动物中具有保守性。TTF-1和HNF-3β的时空表达模式与SP-A和SP-B的模式重叠，支持它们在鸡肺发育中的潜在作用，并证明了脊椎动物呼吸上皮细胞中基因表达调控机制的保守性。
