Genetic Control of SP-B Gene Expression in the Lung

描述（由申请方提供）：表面活性剂蛋白B（SP-B）是一种在肺无纤毛细支气管上皮细胞（Clara细胞）和肺泡II型上皮细胞中产生的79个氨基酸的肽。 SP-B肽储存在板层体中，并与磷脂一起分泌到气道腔中，以促进呼吸周期中表面活性剂磷脂的稳定性和快速扩散。 SP-B基因的突变导致新生儿和基因靶向产生的SP-B缺陷小鼠的致命呼吸窘迫。 SP-B对新生儿出生后肺泡成熟和呼吸适应至关重要。 这项工作的长期目标是确定顺式作用的DNA元件和反式作用的蛋白质因子，控制SP-B基因的时间/空间表达在发育和成熟的肺。 近年来的研究发现，视黄酸受体异源二聚体（RAR/RXR）、甲状腺转录因子1（TTF-1）、核受体辅激活因子（CBP/p300和p160共激活剂，包括SRC-1，TIF 2和ACTR）和信号转导子和转录激活子3（STAT 3）通过增强子区域协同刺激hSP-B转录（-500至-331 bp）。 为了进一步研究，我们将：1）表征RAR α和STAT 3之间相互作用的功能结构域和氨基酸残基; 2）表征hSP-B增强子区域中的RARE和TTF-1顺式作用位点（-500至-331 bp），其使用LacZ转基因小鼠测定细支气管上皮细胞中hSP-B基因的时间/空间表达; 3）利用LacZ转基因小鼠表征决定肺泡II型上皮细胞中hSP-B基因时空表达的顺式作用元件。 这些研究沿着以前的发现，将导致更好地了解肺生物学中SP-B稳态的分子基础。 了解这一点将有助于设计防治先天性和后天性呼吸系统疾病的战略，如肺气肿、呼吸窘迫综合征（RDS）和支气管肺发育不良（BPD），这些疾病是早产儿死亡和发病的主要原因。

DESCRIPTION (provided by applicant): Surfactant protein B (SP-B) is a 79-amino acid peptide produced in pulmonary non-ciliated bronchiolar epithelial cells (Clara cells) and alveolar type II epithelial cells. The SP-B peptide is stored in lamellar bodies and secreted with phospholipids into the airway lumen to facilitate the stability and rapid spreading of surfactant phospholipids during respiratory cycles. Null mutations in the SP-B gene cause lethal respiratory distress in newborn infants and in SP-B deficient mice produced by gene targeting. SP-B is essential for postnatal alveolar maturation and respiratory adaptation in newborns. The long-term goals of this work are to identify cis-acting DNA elements and trans-acting protein factors that control SP-B gene temporal/spatial expression in developing and mature lungs. During the last several years of study, it has been identified that retinoic acid receptor heterodimer (RAR/RXR), thyroid transcription factor 1 (TTF-1), nuclear receptor co-activators (CBP/p300 and p160 co-activators, including SRC-1, TIF2 and ACTR) and signal transducers and activators of transcription 3 (STAT3) cooperatively stimulate hSP-B transcription through an enhancer region (-500 to -331 bp). To extend the study, we will 1): characterize functional domains and amino acid residues that are involved in the interaction between RARalpha and STAT3; 2) characterize RARE and TTF-1 cis-acting sites in the hSP-B enhancer region (-500 to -331 bp) that determine hSP-B gene temporal/spatial expression in bronchiolar epithelial cells using LacZ transgenic mice; 3) characterize cis-acting elements that determine hSP-B gene temporal/spatial expression in alveolar type II epithelial cells using LacZ transgenic mice. These studies along with previous findings will lead to a better understanding of molecular basis for SP-B homeostasis in lung biology. Knowing this will help to design strategies to combat congenital and acquired respiratory diseases such as emphysema, respiratory distress syndrome (RDS) and bronchopulmonary dysplasia (BPD), the leading causes of mortality and morbidity in preterm infants.