Brn-3a deficiency transiently increases expression of calbindin D-28 k and calretinin in the trigeminal ganglion during embryonic development.
Immunohistochemistry for neuron-specific nuclear protein (NeuN), caspase-3, calcitonin gene-related peptide (CGRP), and calcium-binding proteins was performed on the trigeminal ganglion (TG) in wild type and Brn-3a knockout mice at embryonic days 12.5-16.5 (E12.5-E16.5). In Brn-3a knockout mice, the number of NeuN-immunoreactive (ir) neuron profiles increased at E14.5 (40.0% increase) and decreased at E16.5 (28.3% reduction) compared to wild type mice. Caspase-3-ir neuron profiles were abundant in the TG of wild type mice at E12.5-E16.5. However, the loss of Brn-3a decreased the number of caspase-3-ir neuron profiles at E12.5 (69.7% reduction) and E14.5 (51.7% reduction). At E16.5, the distribution of caspase-3-ir neuron profiles was barely affected by the deficiency. CGRP-ir neuron profiles were observed in the TG of wild type mice but not knockout mice at E12.5. At E14.5 and E16.5, CGRP-ir neuron profiles were abundant in both wild type and knockout mice. Calbindin D-28 k (CB)-ir neuron profiles decreased in the TG of mutant mice at E12.5 compared to wild type mice (56.4% reduction). At E14.5, however, Brn-3a deficiency transiently increased CB-ir neuron profiles (169.4% increase as compared to wild type mice). Calretinin (CR)-ir neuron profiles could not be detected in the TG of wild type mice at E12.5-16.5. However, numerous CR-ir neuron profiles transiently appeared in the knockout mouse at E14.5. Parvalbumin (PV)-ir neurons appeared in wild type and knockout mice at E14.5. At this stage, the number of large (>50 mum(2)) PV-ir neuron profiles in knockout mice was fewer than that in wild type mice. The number and cell size of PV-ir neuron profiles were barely affected by the deficiency at E16.5. The present study indicates that the loss of Brn-3a causes increase of TG neurons at E14.5 and decrease of TG neurons at E16.5. It is also suggested that Brn-3a deficiency affects the number and cell size of CGRP- and calcium-binding protein-containing neurons at E12.5 and E14.5. Caspase-3-dependent cell death of CB- and CR-ir neurons may be suppressed by the deficiency at E14.5.
Ichikawa
Hiroyuki
H
Department of Oral Function and Anatomy, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Okayama, 700-8525, Japan. hiroichi@md.okayama-u.ac.jp
Terayama
Ruji
R
Yamaai
Tomoichiro
T
Jacobowitz
David M
DM
Qiu
Feng
F
Xiang
Mengging
M
Sugimoto
Tomosada
T
D000818:Animals; D064032:Calbindin 2; D064026:Calbindins; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism; D053148:Caspase 3 / Q000378:metabolism; D002452:Cell Count; D004268:DNA-Binding Proteins; D047108:Embryonic Development; D007150:Immunohistochemistry; D051379:Mice; D008970:Molecular Weight; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000201:enzymology; D009687:Nuclear Proteins / Q000378:metabolism; D010320:Parvalbumins / Q000378:metabolism; D064030:S100 Calcium Binding Protein G / Q000378:metabolism*; D050819:Transcription Factor Brn-3A / Q000172:deficiency* / Q000378:metabolism; D012668:Trigeminal Ganglion / Q000166:cytology / Q000196:embryology* / Q000201:enzymology / Q000378:metabolism*
C576511:Calb2 protein, mouse; D064032:Calbindin 2; D064026:Calbindins; D004268:DNA-Binding Proteins; D009419:Nerve Tissue Proteins; C492380:NeuN protein, mouse; D009687:Nuclear Proteins; D010320:Parvalbumins; C494189:Pou4f1 protein, mouse; D064030:S100 Calcium Binding Protein G; D050819:Transcription Factor Brn-3A; D053148:Caspase 3; D015740:Calcitonin Gene-Related Peptide