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Changes in HNK-1 distribution during neural crest cell culture
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CHANGES IN HNK-I DISTRIBUTION DURING NEURAL CREST CELL CULTURE M. J. H. Peters van der Sanden, J.H.C. Meijers, Th.M. Luider, A.W.M.van der Kamp, D. Tibboel, J.C. Molenaar. Departments of Cell Biology and Pediatric Surgery, Erasmus University, P.O. Box 1738, 3000 DR Rotterdam, the Netherlands.
INITIAL GABAERGIC EXPRESSION WITH REGARD TO NEURAL INDUCTION PITUELLO F., KAN P., FOULQUIER F. & DUPRAT AM At the late gastrula-early neurula stage some embryonic neuroblasts from neural plate and neural fold present, apparently as a consequence of neural induction, the capability to develop in vitro into different neuronal subpopulations (cholinergic, adrenergic, peptidergic) without ongoing influences from the chordamesoderm (Duprat et al., 1987). Using the same in vitro model system, the aim of the present work was to delineate the abilities of these precursor cells to develop GABAergic traits. The initial appearance and development of GABAergic phenotype has been quantitated by assaying the activity of glutamic acid decarboxylase (GAD). GAD activity was undetectable at the early gastrula stage (st. 8a) and was slightly measurable at the early neurula stage(st. 14-onset of the culture). It increased subsequently over the next ]4 days in vitro. Immunocytochemical studies showed that GABA like immunoreactivity was expressed in a subpopulation of neurons. Thus the developmental program for GAD expression and GABA phenotype maturation is acquired at least in some neuronal precursors near the end of gastrulation i.e. immediately after neural induction.
Cell adhesion molecules carrying the HNK-I epitope play a crucial role in morphogenesis, especially in avian neural crest development. We studied the changes in HNK-I distribution during neural crest cell culture. Trunk neural crest was excised from two-day- old quail embryos and cultured on a fibronectin coating. During the first week of culture, we observed an increase in the number of small stellate HNK-I positive cells, amounting to 85 to 90% of the population. The strongest staining was seen in the cytoplasm in a peri-nuclear halo. After the first week we saw a slight decrease in the small }~qK-i positive cells, an increase in the number of cells with neuronal characteristics (neurofilament and acetylcholinesterase staining) , and occasionally melanocytes. After the second week there was a further decrease in the number of HNK-I positive cells (20-60%). These HNK-I positive cells had a neuronal phenotype and the staining was primarily found on m e m b r a n e s of perikaryon and neurites. Considering the fact that different antigens carry the HNK-I epitope, we speculate that different iocalizations of the HNK-I staining reflect the expression of different antigens in neural crest cell cultures.
662 THE PATTERN OF LENS 35 kDa-POLYPEPTIDE EXPRESSION IN NEURAL RETINA OF RANA TEMPORARIA TADPOLES AND ADULT FROGS. Simirsky, V.N., K.S. Aleinikova, A.T. Mikhailov. Institute of Developmental Biology, USSR Acad. Science, Moscow. In the eye lens of R.temporaria, R.ridlbunda, and R.esculenta 35 kDa-polypeptides were detected which appear to be characteristic only of Ranidae family. They constitute ca. 10-13% of watez--soluble lens proteins. Significant amount of 35 kDa--polypeptides (up to 2%) was detected also in the amphibian neural retina. In the eye lens 35 kDa-polypeptides were first detected during the completion of primary lens fibers formation. During these stages of eye development no such polypeptides were identified in embryonic neural retina. In neural retina of tadpoles 35kDa polypeptides were first detected at the beginning of the limb bud stage of development. During subsequent stages the 35 kDa-polypeptide contents was rather low but increased before the onset of metamorphosis, thus suggesting their role in terminal differentiation of the retina.
$200
661
CHANGES IN HNK-I DISTRIBUTION DURING NEURAL CREST CELL CULTURE M. J. H. Peters van der Sanden, J.H.C. Meijers, Th.M. Luider, A.W.M.van der Kamp, D. Tibboel, J.C. Molenaar. Departments of Cell Biology and Pediatric Surgery, Erasmus University, P.O. Box 1738, 3000 DR Rotterdam, the Netherlands.
INITIAL GABAERGIC EXPRESSION WITH REGARD TO NEURAL INDUCTION PITUELLO F., KAN P., FOULQUIER F. & DUPRAT AM At the late gastrula-early neurula stage some embryonic neuroblasts from neural plate and neural fold present, apparently as a consequence of neural induction, the capability to develop in vitro into different neuronal subpopulations (cholinergic, adrenergic, peptidergic) without ongoing influences from the chordamesoderm (Duprat et al., 1987). Using the same in vitro model system, the aim of the present work was to delineate the abilities of these precursor cells to develop GABAergic traits. The initial appearance and development of GABAergic phenotype has been quantitated by assaying the activity of glutamic acid decarboxylase (GAD). GAD activity was undetectable at the early gastrula stage (st. 8a) and was slightly measurable at the early neurula stage(st. 14-onset of the culture). It increased subsequently over the next ]4 days in vitro. Immunocytochemical studies showed that GABA like immunoreactivity was expressed in a subpopulation of neurons. Thus the developmental program for GAD expression and GABA phenotype maturation is acquired at least in some neuronal precursors near the end of gastrulation i.e. immediately after neural induction.
Cell adhesion molecules carrying the HNK-I epitope play a crucial role in morphogenesis, especially in avian neural crest development. We studied the changes in HNK-I distribution during neural crest cell culture. Trunk neural crest was excised from two-day- old quail embryos and cultured on a fibronectin coating. During the first week of culture, we observed an increase in the number of small stellate HNK-I positive cells, amounting to 85 to 90% of the population. The strongest staining was seen in the cytoplasm in a peri-nuclear halo. After the first week we saw a slight decrease in the small }~qK-i positive cells, an increase in the number of cells with neuronal characteristics (neurofilament and acetylcholinesterase staining) , and occasionally melanocytes. After the second week there was a further decrease in the number of HNK-I positive cells (20-60%). These HNK-I positive cells had a neuronal phenotype and the staining was primarily found on m e m b r a n e s of perikaryon and neurites. Considering the fact that different antigens carry the HNK-I epitope, we speculate that different iocalizations of the HNK-I staining reflect the expression of different antigens in neural crest cell cultures.
662 THE PATTERN OF LENS 35 kDa-POLYPEPTIDE EXPRESSION IN NEURAL RETINA OF RANA TEMPORARIA TADPOLES AND ADULT FROGS. Simirsky, V.N., K.S. Aleinikova, A.T. Mikhailov. Institute of Developmental Biology, USSR Acad. Science, Moscow. In the eye lens of R.temporaria, R.ridlbunda, and R.esculenta 35 kDa-polypeptides were detected which appear to be characteristic only of Ranidae family. They constitute ca. 10-13% of watez--soluble lens proteins. Significant amount of 35 kDa--polypeptides (up to 2%) was detected also in the amphibian neural retina. In the eye lens 35 kDa-polypeptides were first detected during the completion of primary lens fibers formation. During these stages of eye development no such polypeptides were identified in embryonic neural retina. In neural retina of tadpoles 35kDa polypeptides were first detected at the beginning of the limb bud stage of development. During subsequent stages the 35 kDa-polypeptide contents was rather low but increased before the onset of metamorphosis, thus suggesting their role in terminal differentiation of the retina.
$200