Expression of Tp53 and USP7 during development of lungs in mouse model.

Abstract

Background: Much of the human developmental biology, especially at the molecular resolution, has been investigated on a mouse model. Resultantly, it has been demonstrated that lungs development is underpinned by differential and time course dependent expression of many proteins, including Tp53. However, the expression of USP7 (Ubiquitin Specific Protease 7), a deubiquitinase of Tp53 (tumor protein 53), has not been reported for the process. The study focuses on expressional changes of Tp53 and its stabilizer protein USP7 during the development of lungs.

Methodology: Briefly, mice embryos of three different stages of lungs development, pseudoglandular, canalicular and saccular stages, were retrieved from pregnant mice and subjected to histological studies. Morphometric measurements of tubules diameter, tubular wall thickness and tubular lumen diameter were taken during the three stages. Expressions of Tp53 and USP7 in the developing lungs were investigated using immunohistochemistry and statistically analyzed in terms of optical density.

Results: Anatomically, decreases in tubular diameter and tubule wall thickness were observed from the canalicular to the saccular stage, whereas no significant differences were found between the stages in relation to the luminal diameter of tubules. Expression of Tp53 gradually increased in tubules from the pseudoglandular and saccular stage (p=0.0169). However, no difference was observed in interstitial tissue in all three stages. In comparison, USP7 expression was found to increase from pseudoglandular to the canalicular stage in both tubules and interstitial tissue. A positive correlation was only observed between Tp53 and USP7 expression in the interstitial tissue.

Conclusion: The results suggest expression of Tp53 is mainly regulated by USP7 during lungs development in tubules and interstitial tissue, especially between canalicular and saccular stages of lungs development.