Abstract
Myosin Va is an actin-based, processive molecular motor protein highly enriched in the nervous tissue of vertebrates. It has been associated with processes of cellular motility, which include organelle transport and neurite outgrowth. The in vivo expression of myosin Va protein in the developing nervous system of mammals has not yet been reported. We describe here the immunolocalization of myosin Va in the developing rat hippocampus. Coronal sections of the embryonic and postnatal rat hippocampus were probed with an affinity-purified, polyclonal anti-myosin Va antibody. Myosin Va was localized in the cytoplasm of granule cells in the dentate gyrus and of pyramidal cells in Ammon's horn formation. Myosin Va expression changed during development, being higher in differentiating rather than already differentiated granule and pyramidal cells. Some of these cells presented a typical migratory profile, while others resembled neurons that were in the process of differentiation. Myosin Va was also transiently expressed in fibers present in the fimbria. Myosin Va was not detected in germinative matrices of the hippocampus proper or of the dentate gyrus. In conclusion, myosin Va expression in both granule and pyramidal cells showed both position and time dependency during hippocampal development, indicating that this motor protein is under developmental regulation.
Highlights
Brain development requires the coordination of processes that include neuronal proliferation, cell migration and differentiation, synaptogenesis, and programmed cell death
The immunolocalization of myosin Va in mammalian brain from the embryonic to postnatal stage has not yet been described. Since this is a necessary step towards understanding the role of myosin Va in the developing nervous system, we have studied the expression of myosin Va by immunohistochemistry during pre- and postnatal ontogenesis of the rat hippocampus, using an affinity-purified anti-myosin Va antibody
The present report shows that myosin Va exhibits a gradient of expression that appears to accompany the formation of the hippocampal dentate gyrus and Ammon’s horn [5,8,9,10,31]
Summary
Brain development requires the coordination of processes that include neuronal proliferation, cell migration and differentiation, synaptogenesis, and programmed cell death. New neurons are generated throughout life, and are added to the granule cell layer of the dentate gyrus. Granule cells of the dentate gyrus located in the superficial portions of the granule cell layer are generated before those located more deeply, according to an outside-in pattern. This gradient differs from that of the cerebral cortex, where newly generated cells have to migrate through the cell layers formed earlier, resulting in an inside-out pattern [11]. The cytoarchitecture and development of the hippocampus, including the process of neuronal migration guided by glial cells, are well described [5,8,9,10], the participating components and molecular mechanisms involved in these processes remain mostly unknown
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Brazilian Journal of Medical and Biological Research
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
