Calnexin is required for zebrafish posterior lateral line development
Original Article | Published: 9 July 2013
I-Chen Hung1, Bor-Wei Cherng1, Wen-Ming Hsu6,4,* and Shyh-Jye Lee1,2,3,4,5,*
1Institute of Zoology, 2Department of Life Science, 3Center for Biotechnology, 4Center for Systems Biology, 5Research Center for Developmental Biology and Regenerative Medicine, National Taiwan University, Taipei and 6Department of Surgery, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan, R.O.C.
The lateral line is a mechanosensory system in fish and amphibians to detect local water flow and pressure. Development of the posterior lateral line (PLL) originates from the migrating PLL primordium (PLLP). The PLLP deposits neuromasts on the trunk during migration to the tail. Molecular dissection revealed that PLL development is associated with genes mediating cell adhesion, morphogenesis, neurogenesis and development, but the regulatory signaling network is far from completion. To further investigate candidate regulatory genes for lateral line development, we found using whole-mount in situ hybridization that calnexin, an endoplasmic reticular (ER) calcium-binding protein gene, is expressed in PLL neuromasts. Knockdown of calnexin using antisense morpholino oligonucleotides resulted in a dose-dependent reduction in neuromasts and hair cells of the PLL. Using a transgenic claudin b:gfp line, we observed a notably reduced PLLP size, but no significant migration defect in calnexin morphants. Finally, we discovered that the reduced PLLP is associated with a reduction in cell proliferation and an increase in ER stress-dependent apoptosis. These results suggest that calnexin is essential for neuromast formation during lateral line development in the zebrafish.
zebrafish, calnexin, lateral line, neuromast, ER stress