Subcellular localization and function of mouse radial spoke protein 3 in mammalian cells and central nervous system

Abstract

Radial spoke protein 3 (RSP3) was first identified in Chlamydomonas as a component of the radial spoke. The mammalian homologue of the Chlamydomonas RSP3 gene is mainly expressed in testis and developing central nervous system (CNS). However, the subcellular localization and function of mammalian RSP3 in the developing brain and mammalian cells remain poorly understood. Here we show that the mouse RSP3 accumulates at the perinuclear region of Chinese hamster ovary (CHO) and 293T cells. Detailed analysis shows that the mouse RSP3 is not co-localized with the endoplasmic reticulum or Golgi apparatus markers in CHO cells. Using in utero electroporation, we found that over-expression of mammalian RSP3 increases the percentage of neurons reaching the upper cortical plate. In vivo analysis shows that the mouse RSP3 mainly accumulates in the proximal cytoplasmic dilation of the leading process of the migrating cortical neurons. Furthermore, we find that the mammalian RSP3 concentrates in the ependymal cilia as a component of the cilia. Thus, our data provide the first evidence for the subcellular localization and function of mammalian RSP3 in mammalian cells and developing CNS.

The mouse radial spoke protein 3 is a nucleocytoplasmic shuttling protein that promotes neurogenesis

“…Five days after electroporation, the brains were fixed and analyzed. Consistent with our previous study, most of the labeled neurons migrated to the marginal zone (MZ) of the cortical plate (Hu et al 2014). Intriguingly, RSP3 over-expressed brains exhibited thicker upper cortical layers (layer II/III) and higher nuclear density than the control group (Fig.…”

“…Our previous study showed that the cilia of ependymal cells could be labeled with mouse RSP3 by in utero electroporation, and the ependymal cells extend multiple motile cilia from their apical surface into the ventricles (Hu et al 2014). Here, we showed that RSP3 is also specifically located in the primary cilia of RGCs.…”

“…Each RGC possesses a cilium, which is important for mediating a host of extracellular signaling and modulating neurogenesis (Chizhikov et al 2007;Corbit et al 2005;Tong et al 2014). RSP3 is a cilia gene widely expressed from Chlamydomonas to humans, and our previous study demonstrated that RSP3 was specifically located in the cilia of ependymal cells (Hu et al 2014). We therefore hypothesized that RSP3 may also be located in the cilia of RGCs.…”

“…ERK1/2 signaling cascade is one of the key signaling pathways required for cell proliferation and differentiation (Chambard et al 2007). More recently, RSP3 has been shown to accumulate at the prenuclear region of mammalian cell lines and to be specifically located to the ependymal cilia (Hu et al 2014). The ependymal cells in the ventricles extend multiple motile cilia from their apical surface into the ventricles.…”

Parrot Genomes and the Evolution of Heightened Longevity and Cognition

“…The parent paralogs of several other parrot-specific duplicated genes ( CEP83, SLC9A5, RSPH3, LRRC37A ; Table 1) are involved in critical aspects of neuronal cell structure and integrity, including regulation of actin cytoskeleton, microtubule sliding, filopodial extension, and the structure of cilia and dendritic spines, disruptions of which can lead to cognitive impairment [24–27]. LRRC37A , in particular, is a member of a large gene family with involvement in the immune system and in nervous system development, and which is greatly expanded in primates [26].…”