Calnexin is required for zebrafish posterior lateral line development

Area of Science:

• Developmental Biology
• Neuroscience
• Cell Biology

Background:

• The lateral line system in fish and amphibians detects water flow and pressure.
• Posterior lateral line (PLL) development involves migrating primordia (PLLP) that deposit neuromasts.
• Existing research identifies genes for adhesion, morphogenesis, and neurogenesis, but the regulatory network is incomplete.

Purpose of the Study:

• Investigate calnexin's role in posterior lateral line (PLL) development.
• Determine if calnexin regulates neuromast formation and PLL primordium (PLLP) size.

Main Methods:

• Whole-mount in situ hybridization to detect calnexin expression in PLL neuromasts.
• Antisense morpholino oligonucleotides to knock down calnexin expression in zebrafish embryos.
• Analysis of neuromast and hair cell counts in calnexin morphants.
• Observation of PLLP size and migration using a transgenic claudin b:gfp line.
• Assessment of cell proliferation and apoptosis in the PLLP.

Main Results:

• Calnexin is expressed in PLL neuromasts.
• Calnexin knockdown causes a dose-dependent reduction in neuromasts and hair cells.
• Calnexin knockdown leads to a smaller PLLP but does not affect migration.
• Reduced PLLP size correlates with decreased cell proliferation and increased ER stress-induced apoptosis.

Conclusions:

• Calnexin is essential for neuromast formation during zebrafish lateral line development.
• Calnexin influences PLLP size by regulating cell proliferation and apoptosis.
• ER stress is implicated in the observed developmental defects.