title: Changes in expression of Class 3 Semaphorins and their receptors during development of the rat retina and superior colliculus.
abstract: BACKGROUND
  Members of the Semaphorin 3 family (Sema3s) influence the development of the central nervous system, and some are implicated in regulating aspects of visual system development. However, we lack information about the timing of expression of the Sema3s with respect to different developmental epochs in the mammalian visual system. In this time-course study in the rat, we document for the first time changes in the expression of RNAs for the majority of Class 3 Semaphorins (Sema3s) and their receptor components during the development of the rat retina and superior colliculus (SC).
  
  
  RESULTS
  During retinal development, transcript levels changed for all of the Sema3s examined, as well as Nrp2, Plxna2, Plxna3, and Plxna4a. In the SC there were also changes in transcript levels for all Sema3s tested, as well as Nrp1, Nrp2, Plxna1, Plxna2, Plxna3, and Plxna4a. These changes correlate with well-established epochs, and our data suggest that the Sema3s could influence retinal ganglion cell (RGC) apoptosis, patterning and connectivity in the maturing retina and SC, and perhaps guidance of RGC and cortical axons in the SC. Functionally we found that SEMA3A, SEMA3C, SEMA3E, and SEMA3F proteins collapsed purified postnatal day 1 RGC growth cones in vitro. Significantly this is a developmental stage when RGCs are growing into and within the SC and are exposed to Sema3 ligands.
  
  
  CONCLUSIONS
  These new data describing the overall temporal regulation of Sema3 expression in the rat retina and SC provide a platform for further work characterising the functional impact of these proteins on the development and maturation of mammalian visual pathways.
authors: School of Anatomy, Physiology and Human Biology, The University of Western Australia, 35 Stirling Highway, Crawley 6009, WA, Australia. anil@propriocept.com.
authors: Anil
authors: A
authors: Sharma
authors: Chrisna J
authors: CJ
authors: LeVaillant
authors: Giles W
authors: GW
authors: Plant
authors: Alan R
authors: AR
authors: Harvey
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002478:Cells, Cultured; D018507:Gene Expression Regulation, Developmental; D057809:HEK293 Cells; D006801:Humans; D039921:Neuropilins / Q000235:genetics* / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012160:Retina / Q000254:growth & development* / Q000378:metabolism; D039961:Semaphorins / Q000235:genetics* / Q000378:metabolism; D013477:Superior Colliculi / Q000254:growth & development* / Q000378:metabolism
chemical_list: D039921:Neuropilins; D039961:Semaphorins