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Updated: Jul 18, 2026
Immunostaining Phospho-epitopes in Ciliated Organs of Whole Mount Zebrafish Embryos
Published on: February 19, 2016
Knockdown of nuclear Ca2+/calmodulin-dependent protein kinase phosphatase causes developmental abnormalities in
Takaki Nimura1, Noriyuki Sueyoshi, Atsuhiko Ishida
1Department of Life Sciences, Faculty of Agriculture, Kagawa University, Kagawa 761-0795, Japan.
Abstract:
Nuclear Ca2+/calmodulin-dependent protein kinase phosphatase (CaMKP-N) is an enzyme that dephosphorylates and concomitantly downregulates multifunctional Ca2+/calmodulin-dependent protein kinases (CaMKs) in vitro. However, the functional roles of this enzyme in vivo are not well understood. To investigate the biological significance of CaMKP-N during zebrafish embryogenesis, we cloned and characterized zebrafish CaMKP-N (zCaMKP-N). Based on the nucleotide sequences in the zebrafish whole genome shotgun database, we isolated a cDNA clone for zCaMKP-N, which encoded a protein of 633 amino acid residues. Transiently expressed full-length zCaMKP-N in mouse neuroblastoma, Neuro2a cells, was found to be localized in the nucleus. In contrast, the C-terminal truncated mutant lacking RKKRRLDVLPLRR (residues 575-587) had cytoplasmic staining, suggesting that the nuclear localization signal of zCaMKP-N exists in the C-terminal region. Ionomycin treatment of CaMKIV-transfected Neuro2a cells resulted in a marked increase in the phosphorylated form of CaMKIV. However, cotransfection with zCaMKP-N significantly decreased phospho-CaMKIV in ionomycin-stimulated cells. Whole mount in situ hybridization analysis of zebrafish embryos showed that zCaMKP-N is exclusively expressed in the head and neural tube regions. Gene knockdown of zCaMKP-N using morpholino-based antisense oligonucleotides induced significant morphological abnormalities in zebrafish embryos. A number of apoptotic cells were observed in brain and spinal cord of the abnormal embryos. These results suggest that zCaMKP-N plays a crucial role in the early development of zebrafish.
Insights
Nuclear Ca2+/calmodulin-dependent protein kinase phosphatase (CaMKP-N) is vital for zebrafish development. Gene knockdown of zCaMKP-N caused abnormal embryonic development and apoptosis in the brain and spinal cord.
Area of Science:
- Molecular Biology
- Developmental Biology
- Biochemistry
Background:
- Nuclear Ca2+/calmodulin-dependent protein kinase phosphatase (CaMKP-N) dephosphorylates and downregulates Ca2+/calmodulin-dependent protein kinases (CaMKs) in vitro.
- The in vivo functional roles of CaMKP-N remain largely uncharacterized.
Purpose of the Study:
- To investigate the biological significance of CaMKP-N during zebrafish embryogenesis.
- To clone and characterize zebrafish CaMKP-N (zCaMKP-N).
Main Methods:
- Isolation of zCaMKP-N cDNA and expression in Neuro2a cells to determine localization.
- Assessment of zCaMKP-N's effect on CaMKIV phosphorylation in ionomycin-stimulated cells.
- Whole mount in situ hybridization to analyze zCaMKP-N expression patterns in zebrafish embryos.
- Gene knockdown using morpholino antisense oligonucleotides to evaluate functional consequences.
Main Results:
- zCaMKP-N encodes a 633-amino acid protein localized to the nucleus, with the C-terminus acting as a nuclear localization signal.
- zCaMKP-N significantly reduced phospho-CaMKIV levels in stimulated cells.
- zCaMKP-N expression was detected exclusively in the head and neural tube of zebrafish embryos.
- Knockdown of zCaMKP-N resulted in significant morphological abnormalities, including apoptosis in the brain and spinal cord.
Conclusions:
- zCaMKP-N plays a critical role in zebrafish embryogenesis, particularly in neural development.
- The findings highlight the importance of CaMKP-N in regulating CaMK activity in vivo during early development.
