The Kinesin Eg5 participates in Xenopus central nervous system and neural crest development

JUAN P. FERNÁNDEZ; TRISTÁN H. AGÜERO; MANUEL J. AYBAR

San Diego, California, Estados Unidos

Congreso; Society for Neuroscience 2010 Annual Meeting; 2010

Society for Neuroscience

The Kinesin-5 (also known as Eg5 in vertebrates and BimC in invertebrates) is a plus end directed microtubule-based motor protein that is essential for bipolar spindle formation during the early stages of mitosis and meiosis. In cell division, the Eg5 primary function is to maintain spindle bipolarity by generating centrosome-directed forces between antiparallel microtubules in the midzone. Furthermore, previous investigations have showed that Eg5 is expressed in central nervous system (CNS) in developing postmitotic neurons. In rat cultured neurons, pharmacological inhibition as well as neurons depleted of Eg5 results in longer axons and neurons display more branches than controls. In the present study, we have investigated the role of Eg5 at the time of Xenopus neural crest cells development, particularly during their induction as well as its role in the CNS ontogeny. We have cloned the Xenopus Eg5 motor protein. By the whole mount in-situ hybridization approach we showed that the expression pattern of Eg5 gene occurs at the neural fold and neural plate, with exception of the midline, at mid neurula stage in Xenopus embryos. This expression pattern showed correlation with neural crest and CNS markers. In order to evaluate the regulatory role of this gene in the neural crest cells and CNS development, we followed a gain-of-function approach by microinjection of Eg5 mRNA in segmenting embryos. The overexpression of this kinesin produces a decrease in the expression of the neural crest markers (FoxD3, Snail2) and, on the other hand, an increases in the CNS marker Sox2. This fact could suggest a change in the neural crest cell fate towards neural precursors. The microinjection of a specific antisense morpholino oligonucleotide (MO) against Eg5 was able to block the increase of the CNS markers expression. We also carried out rescue experiments in which the inhibitory effects of Eg5 MO were suppressed by the coinjection of Eg5 ARNm. These findings suggest a key role for this motor protein in the development of the neural crest and CNS in Xenopus embryos.