{"id":{"repo_id":"brock","oai_identifier":"oai:brocku.scholaris.ca:10464/4138"},"canonical_url":"https://search.dev.ndltd.org/etd/brock/oai:brocku.scholaris.ca:10464/4138","repository":{"repo_id":"brock","name":"Brock University","base_url":"https://brocku.scholaris.ca/server/oai/request"},"display":{"title":"Elucidation of the Retinoid Signalling Pathway Involved in Axon Guidance in Lymnaea stagnalis and Xenopus laevis","abstract":"The vitamin A metabolite, retinoic acid (RA), is known to play a crucial role in several developmental processes including axial patterning and differentiation. More recently, RA has been implicated in the regenerative process acting through its classical signaling pathway, the nuclear receptors, retinoic acid receptor (RAR) and retinoid X receptor (RXR), to mediate gene transcription. Moreover, RA has been shown to act as a guidance molecule for growth cones of regenerating motorneurons of the pond snail, Lymnaea stagnalis. Our lab has recently shown that RA can induce this morphological response independent of nuclear transcription, however, the role of the retinoid receptors in RA-induced chemoattraction is still unknown. Here, I show that the retinoid receptors, RXR and RAR, may mediate the growth cones response to the metabolically active retinoic acid isomers, all-trans and 9-cis RA, in Lymnaea stagnalis. Data presented here show that both an RXR and RAR antagonist can block growth cone turning in response to application of both isomers. Because no prior investigations have shown growth cone turning of individual vertebrate neurons, I aimed to show that both retinoic acid isomers were capable of inducing growth cone turning of embryonic spinal cord neurons in the frog, Xenopus laevis. For the first time in Xenopus, I showed that both all-trans and 9-cis RA were able to induce significantly more neurite outgrowth from cultured embryonic spinal cord neurons and induce positive growth cone turning of individual growth cones. In addition, I showed that the presence of the RXR antagonist, HX531, blocked 9-cis RA-induced growth cone turning and the RARβ antagonist, LE135, blocked all-trans RA-induced growth cone turning in this species. Evidence provided here shows for the first time, conservation of retinoic acid-induced growth cone turning in a vertebrate model system. In addition, these data show that the receptors involved in this morphological response may be the same in vertebrates and invertebrates.","abstract_html":"The vitamin A metabolite, retinoic acid (RA), is known to play a crucial role in several developmental processes including axial patterning and differentiation. More recently, RA has been implicated in the regenerative process acting through its classical signaling pathway, the nuclear receptors, retinoic acid receptor (RAR) and retinoid X receptor (RXR), to mediate gene transcription. Moreover, RA has been shown to act as a guidance molecule for growth cones of regenerating motorneurons of the pond snail, Lymnaea stagnalis. Our lab has recently shown that RA can induce this morphological response independent of nuclear transcription, however, the role of the retinoid receptors in RA-induced chemoattraction is still unknown. Here, I show that the retinoid receptors, RXR and RAR, may mediate the growth cones response to the metabolically active retinoic acid isomers, all-trans and 9-cis RA, in Lymnaea stagnalis. Data presented here show that both an RXR and RAR antagonist can block growth cone turning in response to application of both isomers. Because no prior investigations have shown growth cone turning of individual vertebrate neurons, I aimed to show that both retinoic acid isomers were capable of inducing growth cone turning of embryonic spinal cord neurons in the frog, Xenopus laevis. For the first time in Xenopus, I showed that both all-trans and 9-cis RA were able to induce significantly more neurite outgrowth from cultured embryonic spinal cord neurons and induce positive growth cone turning of individual growth cones. In addition, I showed that the presence of the RXR antagonist, HX531, blocked 9-cis RA-induced growth cone turning and the RARβ antagonist, LE135, blocked all-trans RA-induced growth cone turning in this species. Evidence provided here shows for the first time, conservation of retinoic acid-induced growth cone turning in a vertebrate model system. In addition, these data show that the receptors involved in this morphological response may be the same in vertebrates and invertebrates.","abstract_has_math":false,"creators":["Rand, Christopher"],"institution":"Brock University","degree_name":"M.Sc. Biological Sciences","degree_level":"Masters","degree_discipline":"Faculty of Mathematics and Science","degree_department":"Department of Biological Sciences","school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2012,"date_issued":"2012-11-07","date_published":"2012-11-07","updated_at":"2026-07-24T01:23:04Z","subjects":["Regeneration","Retinoic Acid","Lymnaea stagnalis","Xenopus laevis","Growth cone guidance"],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/10464/4138","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.department","label":"Department","values":["Department of Biological Sciences"]},{"key":"dc:creator","label":"Author","values":["Rand, Christopher"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2012-11-07T19:45:18Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2012-11-07T19:45:18Z"]},{"key":"dc:date.issued","label":"Date","values":["2012-11-07"]},{"key":"dc:type","label":"Dc Type","values":["Electronic Thesis or Dissertation"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Faculty of Mathematics and Science"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Masters"]},{"key":"thesis:degree_name","label":"Degree Name","values":["M.Sc. 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More recently, RA has been implicated in the regenerative process acting through its classical signaling pathway, the nuclear receptors, retinoic acid receptor (RAR) and retinoid X receptor (RXR), to mediate gene transcription. Moreover, RA has been shown to act as a guidance molecule for growth cones of regenerating motorneurons of the pond snail, Lymnaea stagnalis. Our lab has recently shown that RA can induce this morphological response independent of nuclear transcription, however, the role of the retinoid receptors in RA-induced chemoattraction is still unknown. Here, I show that the retinoid receptors, RXR and RAR, may mediate the growth cones response to the metabolically active retinoic acid isomers, all-trans and 9-cis RA, in Lymnaea stagnalis. Data presented here show that both an RXR and RAR antagonist can block growth cone turning in response to application of both isomers. Because no prior investigations have shown growth cone turning of individual vertebrate neurons, I aimed to show that both retinoic acid isomers were capable of inducing growth cone turning of embryonic spinal cord neurons in the frog, Xenopus laevis. For the first time in Xenopus, I showed that both all-trans and 9-cis RA were able to induce significantly more neurite outgrowth from cultured embryonic spinal cord neurons and induce positive growth cone turning of individual growth cones. In addition, I showed that the presence of the RXR antagonist, HX531, blocked 9-cis RA-induced growth cone turning and the RARβ antagonist, LE135, blocked all-trans RA-induced growth cone turning in this species. Evidence provided here shows for the first time, conservation of retinoic acid-induced growth cone turning in a vertebrate model system. In addition, these data show that the receptors involved in this morphological response may be the same in vertebrates and invertebrates."]},{"key":"dc:title","label":"Title","values":["Elucidation of the Retinoid Signalling Pathway Involved in Axon Guidance in Lymnaea stagnalis and Xenopus laevis"]}]}],"canonical_facts":{"dc:contributor.department":["Department of Biological Sciences"],"dc:creator":["Rand, Christopher"],"dc:date.accessioned":["2012-11-07T19:45:18Z"],"dc:date.available":["2012-11-07T19:45:18Z"],"dc:date.issued":["2012-11-07"],"dc:description.abstract":["The vitamin A metabolite, retinoic acid (RA), is known to play a crucial role in several developmental processes including axial patterning and differentiation. More recently, RA has been implicated in the regenerative process acting through its classical signaling pathway, the nuclear receptors, retinoic acid receptor (RAR) and retinoid X receptor (RXR), to mediate gene transcription. Moreover, RA has been shown to act as a guidance molecule for growth cones of regenerating motorneurons of the pond snail, Lymnaea stagnalis. Our lab has recently shown that RA can induce this morphological response independent of nuclear transcription, however, the role of the retinoid receptors in RA-induced chemoattraction is still unknown. Here, I show that the retinoid receptors, RXR and RAR, may mediate the growth cones response to the metabolically active retinoic acid isomers, all-trans and 9-cis RA, in Lymnaea stagnalis. Data presented here show that both an RXR and RAR antagonist can block growth cone turning in response to application of both isomers. Because no prior investigations have shown growth cone turning of individual vertebrate neurons, I aimed to show that both retinoic acid isomers were capable of inducing growth cone turning of embryonic spinal cord neurons in the frog, Xenopus laevis. For the first time in Xenopus, I showed that both all-trans and 9-cis RA were able to induce significantly more neurite outgrowth from cultured embryonic spinal cord neurons and induce positive growth cone turning of individual growth cones. In addition, I showed that the presence of the RXR antagonist, HX531, blocked 9-cis RA-induced growth cone turning and the RARβ antagonist, LE135, blocked all-trans RA-induced growth cone turning in this species. Evidence provided here shows for the first time, conservation of retinoic acid-induced growth cone turning in a vertebrate model system. In addition, these data show that the receptors involved in this morphological response may be the same in vertebrates and invertebrates."],"dc:identifier.uri":["http://hdl.handle.net/10464/4138"],"dc:language.iso":["eng"],"dc:subject":["Regeneration","Retinoic Acid","Lymnaea stagnalis","Xenopus laevis","Growth cone guidance"],"dc:title":["Elucidation of the Retinoid Signalling Pathway Involved in Axon Guidance in Lymnaea stagnalis and Xenopus laevis"],"dc:type":["Electronic Thesis or Dissertation"],"thesis:degree_discipline":["Faculty of Mathematics and Science"],"thesis:degree_level":["Masters"],"thesis:degree_name":["M.Sc. Biological Sciences"],"thesis:institution_name":["Brock University"]},"updated_at":"2026-07-24T01:23:04Z"}