Control of Crystal Size and Lattice Formation by Starmaker in Otolith Biomineralization

Abstract

The stone-like otoliths from the ears of teleost fishes are involved in balance and hearing and consist of calcium carbonate crystallites embedded in a protein framework. We report that a previously unknown gene, starmaker, is required in zebrafish for otolith morphogenesis. Reduction of starmaker activity by injection of modified antisense oligonucleotides causes a change in the crystal lattice structure and thus a change in otolith morphology. The expression pattern of starmaker, along with the presence of the protein on the growing otolith, suggest that the expression levels of starmaker control the shape of the otoliths.

Expressed sequence tag profiles from calcifying and non-calcifying cultures of Emiliania huxleyi

“…Many biomineral-associated proteins tend to have no distinct secondary or tertiary structure but rather feature extended, repeating b-turn, loop, or random coil conformations (Michenfelder et al 2003;Wustman et al 2002;Xu and Evans 1999;Zhang et al 2002;Zhang et al 2000) and contain specific amino acid sequence motifs. They also tend to be acidic in nature and feature distinct amino acid sequence repeats (Sollner et al 2003).…”

Unipolar assembly of zinc oxide rods manifesting polarity-driven collective luminescence

“…Such processes are abundant in natural systems and are of fundamental importance because these constitute the basic building blocks in many inorganic or biomineralization processes (1)(2)(3)(4)(5)(6)(7)(8)(9)(10). When assembling into larger systems, the constituent crystals orient themselves with respect to each other following certain specific criteria.…”

Mixing model systems: Using zebrafish and mouse inner ear mutants and other organ systems to unravel the mystery of otoconial development

“…Starmaker is homologous to dental sialophosphoprotein (DSPP) in mammals, which is required for the normal mineralization of teeth (Sollner et al, 2003). DSPP mutations have been shown to result in Dentinogenesis Imperfecta (Sreenath et al, 2003).…”

“…Morpholino-mediated knockdown of starmaker leads to a delay in otolith formation as well as loss of the core particles and other proteinaceous components of the developing crystal. In animals injected with very high doses of starmaker morpholino, otoliths consist of inorganic CaCO 3 and have an altered crystal structure (Sollner et al, 2003), most likely due to an inability to coordinate and organize the CaCO 3 into the complex biomineral of the normal otolith. Otolith matrix protein (omp) is the primary matrix protein of the aragonitic fish otolith (Murayama et al, 2000).…”