Localization of mRNA facilitates spatiotemporally controlled protein expression in neurons. In axons, mRNA transport followed by local protein synthesis plays a critical role in axonal growth and guidance. However, it is not yet clearly understood how mRNA is transported to axonal subcellular sites and what regulates axonal mRNA localization. Using a transgenic mouse model in which endogenous β-actin mRNA is fluorescently labeled, we investigated β-actin mRNA movement in axons of hippocampal neurons. We cultured neurons in microfluidic devices to separate axons from dendrites and performed single-particle tracking of axonal β-actin mRNA. Compared with dendritic β-actin mRNA, axonal β-actin mRNA showed less directed motion and exhibited mostly subdiffusive motion, especially near filopodia and boutons in mature dissociated hippocampal neurons. We found that axonal β-actin mRNA was likely to colocalize with actin patches (APs), regions that have a high density of filamentous actin (F-actin) and are known to have a role in branch initiation. Moreover, simultaneous imaging of F-actin and axonal β-actin mRNA in live neurons revealed that moving β-actin mRNA tended to be docked in the APs. Our findings reveal that axonal β-actin mRNA localization is facilitated by actin networks and suggest that localized β-actin mRNA plays a potential role in axon branch formation.
|Original language||English (US)|
|Number of pages||10|
|State||Published - Oct 2022|
Bibliographical noteFunding Information:
This work was supported by the Creative‐Pioneering Researchers Program through Seoul National University (SNU) and the Basic Science Research Program through the National Research Foundation of Korea (NRF) (2020R1A2C2007285 to H.Y.P. and 2021R1A3B1077481 to N.L.J.).
© 2022 The Authors. Traffic published by John Wiley & Sons Ltd.
- actin patch
- axonal β-actin mRNA
- live-cell imaging
- mRNA localization process
- microfluidic device