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A hamster monoclonal antibody that binds to neurons of 8th but not to neurons of 5th cranial sensory ganglia
s117
1103
A HAMSTER MONOCLONAL ANTIBODY THAT BINDS TO NEURONS OF 8TH BUT NOT TO NEURONS OF 5TH CRANIAL SENSORY GANGLIA. SHINOBU C. FUJITA, JUNK0 HASEGAWA AND RIKA KATO, Mitsubishi Kasei Inst. of Life Sci., Miuamioova,Machids,Tokyo 194, Japan
A hybridomaline was establishedusing an Armenianhamster immunized against a homogenate of mouse gestation (E) 12.5 brains. The monoclonal antibody 802Cll produced by this cell line binds to both neural and non-neural tissues of mouse embryos. In cryostat sections of paraformaldehyde-fixed embryos of E9.5 to 16.5, neurons of 8th cranial sensory ganglion are stained, but those of 5th cranial and spinal sensory ganglia are negative. At E12.5, neurons of distal ganglia of 7th, 9th and 10th cranial nerves are stained with lesser intensity, while the proximal ganglia of 9th and 10th nerves are negative. Central nervous system is nearly negative except for the floor plate cells and bundles of positive fibers likely to arise from neurons of positve cranial ganglia. Light microscopic observations on neuronal somata and floor platecells suggest that the antigen may be associated with the cell membrane. This antibody thus demonstrates a molecular heterogeneity among cranial sensory ganglia, and may be useful in analyses of neurogenesis, cell lineage and migration of neurons of cranial ganglia and in studies of cranial ganglia in transgenic mice with abnormal head development.
1104
CHEMOREPULSION OF GROWING UNCROSSED MESENCEPHALIC AXONS BY FLOOR PLATE. A UTAMADA. AND FUJI0 MURAKAMI, Dept. Bionhvs. Engn.. Fat. Enpn. Sci.. Osaka Universitv, Tovonaka. Osaka 560. Japa Vertebrate central nervous system (CNS) develops from a bilaterally symmetrical neural tube. The floor plate (FP) at the ventral midline of the neural tube appears to have attractive cues that guide crossed alar plate axons in the spinal cord and the brain to the cqntralateral side. These cues involve diffusible factors released from the FP. On the other hand, the presence of repulsive cues which keep uncrossed axons on one side was suggested by the findings that FP-deleted zebrafish mutants show Direct evidence and underlying mechanisms for abnormal crossing of normally uncrossed axons. repulsion by the FP, however, remain to be elucidated. To test whether the FP has a repulsive activity on uncrossed axons and whether it is due to diffusible factors, FP explants were co-cultured in collagen gels with explants of the mesencephalon which contain uncrossed+ axons: ventrallygrowing dorsalmost alar plate axons and laterally-growing basal plate axons. Both subsets of axons curved in the gels and grew away from FP explants. Such turning of axons occurred without any contact with FP explants or their processes. These results suggest that the FP releases diffusible factors which repulse subsets of uncrossed axons. Thus it is likely that both chemorepulsion by the FP shown in the present study and chemoattraction by the FP previouly reported play crucial roles in determining axonal growth direction and formation of laterality of projections in the CNS.
1105
Guidance of Cerebellar Plate Axons at the Floor plate: Experimental Manipulation Using WholeMount in Witn, Praparatlon. RYUICHI. RYUTA KAA
FIJI10 MURAKAMI. stty. Toyo-
.
.
.
.
Previously, we examined the in tivo outgrowth and pathfinding of cerebellar plate (CP) axons in the rat hindbrain and obtained evidence for the existence of specific guidance cues at the floor plate in the rostra1 hindbrain. Consistent with our results, further co-culture experiments using collagen gels demonstrated that CP axons are guided towards the ventral midline by a diffusible chemoattractant that may be secreted from the floor plate. In this context, CP axons may require an additional mechanism in order not to be stalled at the floor plate. One possible mechanism for CP axon advance beyond the midline is cooperative interaction between the bilateral CP axons at the midline and subsequent fasciculation with homologous axons. Should this occur, CP axons would fail to cross the midline in the absence of their contralateral counterparts. To test this possibility, in the current study we devised a whole-mount in vitro In control preparations which were preparation which reproduces in vivo development of CP axons. cultured for two days from El 3, CP axons mimicked the in viva development that proceeds from El3 to E15: they crossed the midline and continued to grow for some distance. Similarly, in preparations in which unilateral CP was surgically ablated before CP axon arrival at the midline, remaining CP axons also elongated across the floor plate. These results indicate that CP axons do not require contralateral homologs for guidance beyond the floor plate.
1103
A HAMSTER MONOCLONAL ANTIBODY THAT BINDS TO NEURONS OF 8TH BUT NOT TO NEURONS OF 5TH CRANIAL SENSORY GANGLIA. SHINOBU C. FUJITA, JUNK0 HASEGAWA AND RIKA KATO, Mitsubishi Kasei Inst. of Life Sci., Miuamioova,Machids,Tokyo 194, Japan
A hybridomaline was establishedusing an Armenianhamster immunized against a homogenate of mouse gestation (E) 12.5 brains. The monoclonal antibody 802Cll produced by this cell line binds to both neural and non-neural tissues of mouse embryos. In cryostat sections of paraformaldehyde-fixed embryos of E9.5 to 16.5, neurons of 8th cranial sensory ganglion are stained, but those of 5th cranial and spinal sensory ganglia are negative. At E12.5, neurons of distal ganglia of 7th, 9th and 10th cranial nerves are stained with lesser intensity, while the proximal ganglia of 9th and 10th nerves are negative. Central nervous system is nearly negative except for the floor plate cells and bundles of positive fibers likely to arise from neurons of positve cranial ganglia. Light microscopic observations on neuronal somata and floor platecells suggest that the antigen may be associated with the cell membrane. This antibody thus demonstrates a molecular heterogeneity among cranial sensory ganglia, and may be useful in analyses of neurogenesis, cell lineage and migration of neurons of cranial ganglia and in studies of cranial ganglia in transgenic mice with abnormal head development.
1104
CHEMOREPULSION OF GROWING UNCROSSED MESENCEPHALIC AXONS BY FLOOR PLATE. A UTAMADA. AND FUJI0 MURAKAMI, Dept. Bionhvs. Engn.. Fat. Enpn. Sci.. Osaka Universitv, Tovonaka. Osaka 560. Japa Vertebrate central nervous system (CNS) develops from a bilaterally symmetrical neural tube. The floor plate (FP) at the ventral midline of the neural tube appears to have attractive cues that guide crossed alar plate axons in the spinal cord and the brain to the cqntralateral side. These cues involve diffusible factors released from the FP. On the other hand, the presence of repulsive cues which keep uncrossed axons on one side was suggested by the findings that FP-deleted zebrafish mutants show Direct evidence and underlying mechanisms for abnormal crossing of normally uncrossed axons. repulsion by the FP, however, remain to be elucidated. To test whether the FP has a repulsive activity on uncrossed axons and whether it is due to diffusible factors, FP explants were co-cultured in collagen gels with explants of the mesencephalon which contain uncrossed+ axons: ventrallygrowing dorsalmost alar plate axons and laterally-growing basal plate axons. Both subsets of axons curved in the gels and grew away from FP explants. Such turning of axons occurred without any contact with FP explants or their processes. These results suggest that the FP releases diffusible factors which repulse subsets of uncrossed axons. Thus it is likely that both chemorepulsion by the FP shown in the present study and chemoattraction by the FP previouly reported play crucial roles in determining axonal growth direction and formation of laterality of projections in the CNS.
1105
Guidance of Cerebellar Plate Axons at the Floor plate: Experimental Manipulation Using WholeMount in Witn, Praparatlon. RYUICHI. RYUTA KAA
FIJI10 MURAKAMI. stty. Toyo-
.
.
.
.
Previously, we examined the in tivo outgrowth and pathfinding of cerebellar plate (CP) axons in the rat hindbrain and obtained evidence for the existence of specific guidance cues at the floor plate in the rostra1 hindbrain. Consistent with our results, further co-culture experiments using collagen gels demonstrated that CP axons are guided towards the ventral midline by a diffusible chemoattractant that may be secreted from the floor plate. In this context, CP axons may require an additional mechanism in order not to be stalled at the floor plate. One possible mechanism for CP axon advance beyond the midline is cooperative interaction between the bilateral CP axons at the midline and subsequent fasciculation with homologous axons. Should this occur, CP axons would fail to cross the midline in the absence of their contralateral counterparts. To test this possibility, in the current study we devised a whole-mount in vitro In control preparations which were preparation which reproduces in vivo development of CP axons. cultured for two days from El 3, CP axons mimicked the in viva development that proceeds from El3 to E15: they crossed the midline and continued to grow for some distance. Similarly, in preparations in which unilateral CP was surgically ablated before CP axon arrival at the midline, remaining CP axons also elongated across the floor plate. These results indicate that CP axons do not require contralateral homologs for guidance beyond the floor plate.