biostudies-literaturevon der Heyde BJohn Templeton Foundation (JTF)Wellcome Truste2425759122https://www.ebi.ac.uk/biostudies/studies/S-EPMC12377771biostudies-literatureUnknown122(33)The evolution of multicellularity involved the transformation of a simple cell wall of unicellular ancestors into a complex, multifunctional extracellular matrix (ECM). A suitable model organism to study the formation and expansion of an ECM during ontogenesis is the multicellular green alga <i>Volvox carteri</i>, which, along with the related volvocine algae, produces a complex, self-organized ECM composed of multiple substructures. These self-assembled structures primarily consist of hydroxyproline-rich glycoproteins, a major component of which is pherophorins. To investigate the geometry of the growing ECM, we fused the <i>yfp</i> gene with the gene for pherophorin II (PhII) in <i>V. carteri</i>. Confocal microscopy reveals PhII:YFP localization at key ECM structures, including the bounProceedings of the National Academy of Sciences of the United States of AmericaSpatiotemporal distribution of the glycoprotein pherophorin II reveals stochastic geometry of the growing ECM of &lt;i&gt;Volvox carteri&lt;/i&gt;.PMC1237777162220307079/Z/23/Z207510/Z/17/Zvon der Heyde ELHohn SSMHGoldstein REvon der Heyde BSrinivasan ABirwa SKHallmann AfalseSpatiotemporal distribution of the glycoprotein pherophorin II reveals stochastic geometry of the growing ECM of &lt;i&gt;Volvox carteri&lt;/i&gt;.The evolution of multicellularity involved the transformation of a simple cell wall of unicellular ancestors into a complex, multifunctional extracellular matrix (ECM). A suitable model organism to study the formation and expansion of an ECM during ontogenesis is the multicellular green alga <i>Volvox carteri</i>, which, along with the related volvocine algae, produces a complex, self-organized ECM composed of multiple substructures. These self-assembled structures primarily consist of hydroxyproline-rich glycoproteins, a major component of which is pherophorins. To investigate the geometry of the growing ECM, we fused the <i>yfp</i> gene with the gene for pherophorin II (PhII) in <i>V. carteri</i>. Confocal microscopy reveals PhII:YFP localization at key ECM structures, including the boun2025-01-01T00:00:00Z2025 Aug2026-05-10T04:26:45.789Z2026-04-08T01:29:31.24ZS-EPMC123777714079483810.1073/pnas.2425759122