Control of biosilica morphology and mechanical performance by the conserved diatom gene Silicanin-1

Abstract

The species-specifically patterned biosilica cell walls of diatoms are paradigms for biological mineral morphogenesis and the evolution of lightweight materials with exceptional mechanical performance. Biosilica formation is a membrane-mediated process that occurs in intracellular compartments, termed silica deposition vesicles (SDVs). Silicanin-1 (Sin1) is a highly conserved protein of the SDV membrane, but its role in biosilica formation has remained elusive. Here we generate Sin1 knockout mutants of the diatom Thalassiosira pseudonana . Although the mutants grow normally, they exhibit reduced biosilica content and morphological aberrations, which drastically compromise the strength and stiffness of their cell walls. These results identify Sin1 as essential for the biogenesis of mechanically robust diatom cell walls, thus providing an explanation for the conservation of this gene throughout the diatom realm. This insight paves the way for genetic engineering of silica architectures with desired structures and mechanical performance.

Microbe‐Mediated Extracellular and Intracellular Mineralization: Environmental, Industrial, and Biotechnological Applications

“…[ 175 ] The nanopatterned biosiliceous organic–inorganic hybrid composite is precipitated within the SDVs and ultimately become the frustules (Figure 3C). [ 176 ]…”

Computational Analysis of The Effects of Nitrogen Source and Sin1 Knockout on Biosilica Morphology in The Model Diatom Thalassiosira Pseudonana

“…4b). The previous interpretation of missing cross-connection in the sin1 knockout mutants [17], was thus a misinterpretation of a phenotype that exhibits weakly silicified cross-links. This result demonstrated that by applying both skeletonization methods, a more realistic description of the valve phenotypes could be obtained.…”

“…While biosilica functionalization using LiDSI is well developed and even enables regioselective incorporation of proteins [30], the genetic engineering of biosilica structure is still in its infancy. Only quite recently, the first genetically induced morphological mutants were generated in diatoms through knockdown and knockout of specific genes [15,17]. One of the mutants (Sin1KO), which was generated by knocking out the sin1 gene in T. pseudonana, exhibited a pleiotropic phenotype.…”

Microbial Nanotechnology: Challenges and Prospects for Green Biocatalytic Synthesis of Nanoscale Materials for Sensoristic and Biomedical Applications

“…Such antibody-labelled genetically modified diatom enables an in vitro selectively cell targeting and selectively killing of neuroblastoma and B-lymphoma cells [113]. Furthermore, the role of gene Silicanin-1 in the control of biosilica morphology has been recently highlighted in Thalassiosira pseudonana, opening new possibilities for future genetic engineering of frustules architectures [114]. A deeper knowledge of biosilicification process as well as the role of organic components of diatom frustules (i.e., proteins silaffins and long-chain polyamines) in biogenesis and formation of nanopatterns in diatom frustules are still a challenge.…”