Single-Cell Biophysics: Measurement, Modulation, and Modeling

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Single-Cell Biophysics: Measurement, Modulation, and Modeling Poster Abstracts
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78-POS Board 39
Superresolution Imaging Reveals Protein-Templated Patterns for Biosilica Formation
Philip Gröger1, Nicole Poulsen1, Jennifer Klemm1, Nils Kröger1,2, Michael Schlierf1.
1TU Dresden, Dresden, Germany, 2TU Dresden, Dresden, Germany.
The intricate, genetically controlled biosilica nano- and micropatterns produced by diatoms are a
testimony for biology’s ability to control mineral formation (biomineralization) at the nanoscale
and regarded as paradigm for nanotechnology. Several recently discovered protein families
involved in diatom biosilica formation remain tightly associated with the final biosilica structure.
Determining the locations of biosilica-associated proteins with high precision is therefore
expected to provide clues to their roles in biosilica morphogenesis. To achieve this, we introduce
single-molecule localization microscopy to diatoms based on photo-activated light microscopy
(PALM) to overcome the diffraction limit. We identified six photo-convertible fluorescent
proteins (FPs) that can be utilized for PALM in the cytoplasm of Thalassiosira pseudonana.
However, only three FPs that share a common molecular conversion-mechanism were also
functional when embedded in diatom biosilica and localized with a mean precision of 25 nm to
resolve structural features. Further co-localization studies on proteins of the Cingulin family
when extracted from the biosilica using a combined two-color PALM+STORM approach
revealed characteristic protein filaments with distinct protein specific patterns. The enhanced
microscopy techniques introduced here for diatoms will aid in elucidating the molecular
mechanism of silica biomineralization as well as other aspects of diatom cell biology.