期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2022
卷号：119
期号：37
DOI：10.1073/pnas.2208465119
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Significance
The insulin-like growth factor II mRNA-binding protein (IGF2BP1/IMP1/ZBP1) is an important RNA-binding protein (RBP) involved in regulating mRNA fate. Previous work on IGF2BP1 has served as an important model for understanding other RBPs. In this work, we present an IGF2BP1 knockout mouse model with endogenously labeled target mRNA (
β-actin). This approach will expand our understanding of a critical RBP. In this study, we establish the essential role of IGF2BP1 in development and postnatal survival. In the absence of IGF2BP1, we also report endogenous
β-actin mRNA transport and anchoring are significantly decreased at steady state. Additionally, we find that IGF2BP1 knockout neurons have increased actin protein content. Hence, IGF2BP1 is a major regulator of cell fate including transport, anchoring, and translation.
Gene expression is tightly regulated by RNA-binding proteins (RBPs) to facilitate cell survival, differentiation, and migration. Previous reports have shown the importance of the Insulin-like Growth Factor II mRNA-Binding Protein (IGF2BP1/IMP1/ZBP1) in regulating RNA fate, including localization, transport, and translation. Here, we generated and characterized a knockout mouse to study RBP regulation. We report that IGF2BP1 is essential for proper brain development and neonatal survival. Specifically, these mice display disorganization in the developing neocortex, and further investigation revealed a loss of cortical marginal cell density at E17.5. We also investigated migratory cell populations in the IGF2BP1
−
/
−
mice, using BrdU labeling, and detected fewer mitotically active cells in the cortical plate. Since RNA localization is important for cellular migration and directionality, we investigated the regulation of
β-actin messenger RNA (mRNA), a well-characterized target with established roles in cell motility and development. To aid in our understanding of RBP and target mRNA regulation, we generated mice with endogenously labeled
β-actin mRNA (IGF2BP1
−
/
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;
β-actin-MS2
+
/
+
). Using endogenously labeled
β-actin transcripts, we report IGF2BP1
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/
−
neurons have increased transcription rates and total
β-actin protein content. In addition, we found decreased transport and anchoring in knockout neurons. Overall, we present an important model for understanding RBP regulation of target mRNA.
