The stack was then flattened into a maximum z-projection Selleckchem BI-2536 using ImageJ. For quantifications presented in Figure 2, lengths were measured within the original confocal z-slices using the line tool in Volocity. Statistical tests were performed using InStat (GraphPad). We would like to thank G. Banker (pBa-Kif5c560-YFP) and D.L. Stemple (lamα1 morpholino) for the generous gift of reagents; H. Lynn and C.J. Wilkinson for molecular cloning; and A. McNabb, T. Dyl, and K.L. Scott for fish maintenance. We are grateful to C.-B. Chien,

C. Norden, P. Jusuf, and K.M. Kwan for suggestions on the manuscript. W.A.H. conceived of and supervised the study. O.R. performed and analyzed all of the experiments presented. O.R and W.A.H. designed the experiments and wrote the manuscript. L.P. helped in the creation of the Centrin-GFP transgenic, and with the initial blastomere transplantation experiments. F.R.Z. performed the preliminary in vitro Lam1 bead and Centrin-GFP experiments. O.R. is a member of the Wellcome Trust programme in Developmental Biology, and is also funded

by the Cambridge Overseas Trust. This work was supported by a Wellcome Trust Programme Grant to W.A.H. “
“Neurons extend processes over long distances during Selleck DAPT development, establishing complex yet precise connections to achieve mature neuronal functions. During this process growing neuronal processes recognize and interpret numerous cues as they navigate to their appropriate targets (Raper and Mason, 2010 and Tessier-Lavigne and Goodman, 1996). In both vertebrates and invertebrates,

longitudinal neural tracts extending along the anterior-posterior axis within the nerve cord serve to exchange and integrate information between different body segments and the brain. To establish these tracts, developing neurites must extend across segmental boundaries, already often fasciculating with related neurites from a myriad of possible partners in adjacent segments. In addition, longitudinal pathways often receive neural input from sensory afferents and other local interneurons critical for processing specific sensory information and modulating appropriate motor responses. These two aspects of longitudinal tract assembly could be intrinsically linked to better achieve select targeting of neuronal projections that belong to the same circuit. Cellular experiments in both invertebrates and vertebrates demonstrate the importance of contact with pioneer neurons for the establishment of continuous rostral-caudal neuronal pathways (Goodman et al., 1984, Kuwada, 1986 and Wolman et al., 2008). Genetic analyses in the Drosophila embryonic CNS reveal molecular mechanisms governing important aspects of longitudinal pathway organization within the nerve cord.