The role of the putative LCPA-synthase ThaAPT4 in cell wall morphogenesis of Thalassiosira pseudonana

Research output: Types of ThesisMaster thesis



Diatoms are unicellular eukaryotic algae that produce intricately structured cell walls made of nanopatterned amorphous silica (SiO2). Silica formation in diatoms appears to depend on long-chain polyamines (LCPAs), which contain a propylamine backbone with a variable degree of N-methylation and chain length. Genome analysis of Thalassiosira pseudonana recently revealed four gene fusions encoding the polyamine biosynthetic domains S-Adenosylmethionine decarboxylase (AdoMetDC) and aminopropyltransferase. One of these gene fusions, ThaAPT4 further contains an N-methyltransferase (SET domain). This enzymatic toolkit could be sufficient to synthesize LCPAs with all characteristic features found in T. pseudonana LCPAs. Using a CRISPR/Cas9 mediated knockout, I show that ThaAPT4 is indeed an LCPA synthase, capable of iterative elongation of the aminopropyl backbone of LCPAs and internal N-methylation. However, the ThaAPT4 knockout did not affect the terminal N-methylations found in T. pseudonana LCPAs. I have shown by Scanning electron microscopy and silicon content determination that the perturbations in LCPA biosynthesis did not affect the cell wall morphology.


Original languageEnglish
Qualification levelMaster of Science
Defense Date (Date of certificate)28 Apr 2022
Publication statusPublished - 1 Apr 2022
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External IDs

ORCID /0000-0002-1454-7897/work/141543122