Semaphorins 3A Research Articles

RETRACTED: Ontogeny of semaphorins 3A and 3F and their receptors neuropilins 1 and 2 in the kidney

This article has been retracted at the request of the authors.Reason: In July of 2002, Mechanisms of Development (MoD) started publishing its section Gene Expression Patterns (until then included under the Mechanisms of Development title) under the separate title Gene Expression Patterns, as a separate section of Mechanisms of Development. This change was clearly communicated at the time in the journal and on the journal's web site. The Editors also informed the authors about this.Early 2003, it came to our attention that a mistake was made during the split with regard to a number of Gene Expression Patterns articles in the pipeline (between initial submission and final acceptance). Due to a miscommunication for which the publisher accepts the responsibility, not all the editors used the same cut-off date for the split. As a result, some articles have been published under the Gene Expression Patterns title that should have been published in the main section of Mechanisms of Development. The publisher is very much aware of the serious nature of this mistake and we apologise to the authors, readers and editors of the journal.In the first months of 2003, we consulted with a number of the authors involved to discuss possible options to remedy the situation, and at the request of the authors, we agreed to retract the articles of the authors concerned, who requested this. We also agreed to offer this opportunity to those authors who were notified by the editors, but who misunderstood the message due to the fact that the proofs of their articles still had the MoD logo and title on the opening page. This article has been re-published under the Mechanisms of Development title, in a special supplement to volume 119.The Publisher

Age-Dependent Effects of Secreted Semaphorins 3A, 3F, and 3E on Developing Hippocampal Axons: In Vitro Effects and Phenotype of Semaphorin 3A (−/−) Mice

We studied the role of Semaphorins in the formation of hippocampal connections at embryonic and early postnatal stages. We show that the embryonic entorhinal cortex has a repulsive effect on embryonic hippocampal axons that disappears gradually at postnatal stages. Such chemorepulsion is blocked by Neuropilin-1 and -2 blocking antibodies. However, at perinatal stages, the inner layers of the entorhinal cortex attract CA1 axons. At these stages, Sema3A and Sema3F bind commissural and entorhinal axons. Sema3A and Sema3F repel hippocampal axons at E14-P2, but not at E13. A similar spatiotemporal pattern of chemorepulsion is observed for Sema3A on entorhinal axons, in contrast to Sema3F, which repels these axons only at postnatal ages. Sema3E also repels hippocampal axons but exclusively at E14. We show that Sema3A and Sema3F can induce the collapse of hippocampal growth cones and that membrane-bound Sema3A and Sema3F can guide hippocampal axons in the stripe assay. In sema3A (−/−) mice, the entorhinohippocampal projection is largely normal although single axons innervate aberrantly the stratum radiatum and the hilus. Thus, the chemorepulsion evoked by Sema3A, Sema3E, and Sema3F is dynamically regulated in the developing hippocampal formation.