title: Sites of origin and developmental dynamics of the neurons in the core and shell regions of torus semicircularis in the Chinese softshell turtle (Pelodiscus sinensis).
abstract: To know the embryogenesis of the core and shell regions of the midbrain auditory nucleus, a single dose of [(3)H]-thymidine was injected into the turtle embryos at peak stages of neurogenesis in the shell and core of the torus semicircularis. Following sequential survival times, labeled neurons and the dynamics of cell proliferation were examined. The expression of vimentin (VM), reelin, calbindin, parvalbumin, and substance P were also studied. The results showed that: 1) progenitor cells for the core and shell regions were generated in different sites of the ventricular zone; 2) the length of the cell cycle or S-phase for the shell region were both longer than those for the core region (4.7 and 3.2 hours longer, respectively), suggesting that mitotic activity in the core region is higher than it is in the shell region; 3) the elongated cell bodies of the labeled core and shell cells had close apposition to VM fibers, suggesting that the migration of these cells is guided by VM fibers; 4) the germinal sites of the core and shell constructed by projecting the orientation of radial VM fibers back to the ventricular zone was consistent with those obtained by short and sequential survival [(3)H]-thymidine radiography; and 5) the beginning of positive staining for parvalbumin in the core region was interposed between those for calbindin and substance P in the shell regions. This study contributes to the understanding of how auditory nuclei are organized and how their components developed and evolved.
authors.affiliation: Key Laboratory for Cell Proliferation and Regulation Biology, Ministry of Education, Beijing Normal University, Beijing, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Xi
authors.forename: Qiong
authors.initials: Q
authors.lastname: Chen
authors.forename: Shao-Ju
authors.initials: SJ
authors.lastname: Zeng
authors.forename: Yu-Tao
authors.initials: YT
authors.lastname: Lin
authors.forename: Yu-Fang
authors.initials: YF
authors.lastname: Huang
authors.forename: Yu
authors.initials: Y
authors.lastname: Liu
authors.forename: Xin-Wen
authors.initials: XW
authors.lastname: Zhang
authors.forename: Ming-Xue
authors.initials: MX
authors.lastname: Zuo
mesh_terms: D000818:Animals; D001306:Auditory Pathways / Q000033:anatomy & histology* / Q000196:embryology*; D064026:Calbindins; D015816:Cell Adhesion Molecules, Neuronal / Q000378:metabolism; D049109:Cell Proliferation; D016326:Extracellular Matrix Proteins / Q000378:metabolism; D006801:Humans; D008636:Mesencephalon / Q000033:anatomy & histology* / Q000196:embryology*; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D010320:Parvalbumins / Q000378:metabolism; D000091042:Reelin Protein; D064030:S100 Calcium Binding Protein G / Q000378:metabolism; D012697:Serine Endopeptidases / Q000378:metabolism; D013373:Substance P / Q000378:metabolism; D013936:Thymidine / Q000378:metabolism; D014426:Turtles / Q000033:anatomy & histology* / Q000196:embryology*
chemical_list: D064026:Calbindins; D015816:Cell Adhesion Molecules, Neuronal; D016326:Extracellular Matrix Proteins; D009419:Nerve Tissue Proteins; D010320:Parvalbumins; D000091042:Reelin Protein; D064030:S100 Calcium Binding Protein G; D013373:Substance P; C000717127:RELN protein, human; D012697:Serine Endopeptidases; D013936:Thymidine