Publications
bioRxivJun 2025 DOI:
10.1101/2025.06.24.661030

Defining the minimal structural requirements of DivIVA in filamentous Actinomycetota

Lubbers, Maarten; Bajramović, Belmin; Ongenae, Véronique; Willemse, Joost; Bruin, Dieuwertje de; Mulder, Niels; Vriesendorp, Bastienne; Barona‐Gómez, Francisco; Briegel, Ariane; Wezel, Gilles P. van; Flärdh, Klas; Claessen, Dennis
Product Used
NGS
Abstract
The morphogenetic protein DivIVA exhibits diverse functions across bacterial phyla. In Bacillota, DivIVA is primarily involved in cell division, whereas in Actinomycetota, it plays a central role in coordinating polar growth. Due to its essential nature, gaining insight into DivIVA function is challenging. Here we report on the functionality of truncated DivIVA proteins, using a unique divIVA deletion mutant created in cell wall-deficient Kitasatospora viridifaciens L-forms. DivIVA comprises an N-terminal domain, two coiled-coil regions separated by an intercoil linker, and a C-terminal domain. Deleting either the intercoil or the C-terminal region impacted branching dynamics. We also created a minimized variant wherein both were deleted simultaneously, containing the N-terminus and fused coiled-coils, resembling DivIVA from unicellular bacteria. Expression of this minimized variant resulted in severe growth defects. Cells exhibited a strong increase in hyphal width and cell wall thickness, accompanied by frequent tip bursting. Finally, we successfully introduced chimeric DivIVA from the unicellular actinobacterium Mycolicibacterium smegmatis with an N-terminal domain of Kitasatospora viridifaciens, demonstrating functional conservation within the phylum. In contrast, a chimeric DivIVA from Bacillus subtilis could not support growth, underscoring that polar growth is encoded within Actinomycetota-specific amino acid motifs encoded in the first and second coiled-coil. These findings enhance our understanding of the structure-function relationship for DivIVA and present new opportunities to study polar growth.
Product Used
NGS

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