In utero pulse injection of isotopic amino acids quantifies protein turnover rates during murine fetal development

Summary

Protein translational control is critical for ensuring that the fetus develops correctly and that necessary organs and tissues are formed and functional. We developed an in utero method to quantify tissue-specific protein dynamics by monitoring amino acid incorporation into the proteome after pulse injection. Fetuses of pregnant mice were injected with isotopically labeled lysine and arginine via the vitelline vein at various embyonic days, and organs and tissues were harvested. By analyzing the nascent proteome, unique signatures of each tissue were identified by hierarchical clustering. In addition, the quantified proteome-wide turnover rates were calculated between 3.81E−5 and 0.424 h ⁻¹. We observed similar protein turnover profiles for analyzed organs (e.g., liver vs. brain); however, their distributions of turnover rates vary significantly. The translational kinetic profiles of developing organs displayed differentially expressed protein pathways and synthesis rates, which correlated with known physiological changes during mouse development.

Graphical abstract

Highlights

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  We report an in utero amino acid pulse injection method

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  This method can be used to study protein turnover in fetal development

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  Tissue-specific protein dynamics can be studied for the nascent proteome

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  Protein turnover can be monitored at various gestational stages

Motivation

Protein translational control is a highly regulated step in the gene expression program during mammalian development; however, quantitative techniques to monitor protein synthesis rates in a developing fetus ( in utero) are limited. Here, we developed an in utero stable isotope labeling approach to quantify tissue-specific protein dynamics of the nascent proteome during mouse fetal development.

Abstract

Baeza et al. report an in utero method to monitor amino acid incorporation into the proteome after pulse injection. This method enables quantification of the nascent proteome during various gestational stages in a tissue-specific manner and provides insights into fetal proteome turnover.