More Like this

1. Cleavage-furrow formation without F-actin in Chlamydomonas

   https://doi.org/10.1073/pnas.1920337117  

   Onishi, Masayuki; Umen, James_G; Cross, Frederick_R; Pringle, John_R (July 2020, Proceedings of the National Academy of Sciences)

   Significance Studies of eukaryotic cell division have focused on the actomyosin ring, whose filaments of F-actin and myosin-II are hypothesized to generate the contractile force for ingression of the cleavage furrow. However, myosin-II has a very limited taxonomic distribution, whereas division by furrowing is much more widespread. We used the green algaChlamydomonas reinhardtiito investigate how a furrow can form without myosin-II and the potential roles of F-actin in this process. Although F-actin was associated with ingressing furrows, its complete removal only modestly delayed furrowing, suggesting that an actin-independent mechanism (possibly involving microtubules) drives furrow ingression. Such a mechanism presumably emerged early in eukaryotic evolution and may still underlie cell division in a diverse range of modern species. 

   more » « less
2. Expanding the toolkit for ploidy manipulation in Chlamydomonas reinhardtii

   https://doi.org/10.1111/nph.70095  

   Van_de_Vloet, Antoine; Prost‐Boxoen, Lucas; Bafort, Quinten; Paing, Yunn Thet; Casteleyn, Griet; Jomat, Lucile; Lemaire, Stéphane D; De_Clerck, Olivier; Van_de_Peer, Yves (May 2025, New Phytologist)

   Summary Whole‐genome duplications, widely observed in plant lineages, have significant evolutionary and ecological impacts. Yet, our current understanding of the direct implications of ploidy shifts on short‐ and long‐term plant evolution remains fragmentary, necessitating further investigations across multiple ploidy levels.Chlamydomonas reinhardtiiis a valuable model organism with profound potential to study the impact of ploidy increase on the longer term in a laboratory environment. This is partly due to the ability to increase the ploidy level.We developed a strategy to engineer ploidy inC. reinhardtiiusing noninterfering, antibiotic, selectable markers. This approach allows us to induce higher ploidy levels inC. reinhardtiiand is applicable to field isolates, which expands beyond specific auxotroph laboratory strains and broadens the genetic diversity of parental haploid strains that can be crossed. We implement flow cytometry for precise measurement of the genome size of strains of different ploidy.We demonstrate the creation of diploids, triploids, and tetraploids by engineering North American field isolates, broadening the application of synthetic biology principles inC. reinhardtii. However, our newly formed triploids and tetraploids show signs of rapid aneuploidization.Our study greatly facilitates the application ofC. reinhardtiito study polyploidy, in both fundamental and applied settings. 

   more » « less
3. Chlamydomonas

   https://doi.org/10.1016/j.cub.2024.05.039  

   Tulin, Frej; Clark-Cotton, Manuella R; Onishi, Masayuki (July 2024, Current Biology)

   Tulin et al. introduce Chlamydomonas, a unicellular green alga commonly used as a microbial reference system for plants and animals. 

   more » « less
4. Identification of Chlamydomonas reinhardtii endogenous genic flanking sequences for improved transgene expression

   https://doi.org/10.1111/tpj.13731  

   López-Paz, Cristina; Liu, Dianyi; Geng, Sa; Umen, James G. (December 2017, The Plant Journal)
5. The structure of Chlamydomonas LOV1 as revealed by time-resolved serial synchrotron crystallography

   https://doi.org/10.1107/S2052252524008327  

   Schmidt, Marius (September 2024, IUCrJ)

   The photo-reaction of the LOV1 domain of the Chlamydomonas reinhardtii phototropin is investigated by room temperature time-resolved serial crystallography. A covalent adduct forms between the carbon-4a atom of the central flavin-mononucleotide chromophore and a protein cysteine. The structure of the adduct is very similar to that of LOV2 determined from the maidenhair fern Phy3 23 years ago. 

   more » « less