ORCID Profile
0000-0003-2356-3351
Current Organisation
University of Cambridge
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Publisher: Springer Science and Business Media LLC
Date: 16-12-2021
Publisher: Cold Spring Harbor Laboratory
Date: 04-05-2023
DOI: 10.1101/2023.05.03.539051
Abstract: Metamonads are a erse group of heterotrophic microbial eukaryotes adapted to living in hypoxic environments. All metamonads but one harbour metabolically altered ‘mitochondrion-related organelles’ (MROs) with reduced functions relative to aerobic mitochondria, however the degree of reduction varies markedly over the metamonad tree. To further investigate metamonad MRO ersity, we generated high quality draft genomes, transcriptomes, and predicted proteomes for five recently discovered free-living metamonads. Phylogenomic analyses place these organisms in a clade sister to the Fornicata – a group of metamonads that includes parasitic and free-living diplomonads and Carpediemonas -like organisms. Extensive bioinformatic analyses of the manually curated gene models showed that these organisms have extremely reduced MROs in comparison to other free-living metamonads. Loss of the mitochondrial iron-sulfur cluster (ISC) assembly system in some organisms in this group appears to be linked to the acquisition in their common ancestral lineage of a SUF-like minimal system (SMS) Fe/S cluster pathway through lateral gene transfer (LGT). One of the isolates, named ‘RC’, appears to have undergone even more drastic mitochondrial reduction losing almost all other detectable MRO-related functions. The extreme mitochondrial reduction observed within this free-living anaerobic protistan clade is unprecedented and demonstrates that mitochondrial functions, under some conditions, can be almost completely lost even in free-living organisms.
Publisher: Cold Spring Harbor Laboratory
Date: 15-03-2021
DOI: 10.1101/2021.03.14.435266
Abstract: Cells must replicate and segregate their DNA with precision. In eukaryotes, these processes are part of a regulated cell-cycle that begins at S-phase with the replication of DNA and ends after M-phase. Previous studies showed that these processes were present in the last eukaryotic common ancestor and the core parts of their molecular systems are conserved across eukaryotic ersity. However, some unicellular parasites, such as the metamonad Giardia intestinalis , have secondarily lost components of the DNA processing and segregation apparatuses. To clarify the evolutionary history of these systems in these unusual eukaryotes, we generated a high-quality draft genome assembly for the free-living metamonad Carpediemonas membranifera and carried out a comparative genomics analysis. We found that parasitic and free-living metamonads harbor a conspicuously incomplete set of canonical proteins for processing and segregating DNA. Unexpectedly, Carpediemonas species are further streamlined, lacking the origin recognition complex, Cdc6 and other replisome components, most structural kinetochore subunits including the Ndc80 complex, as well as several canonical cell-cycle checkpoint proteins. Carpediemonas is the first eukaryote known to have lost this large suite of conserved complexes, suggesting that it has a highly unusual cell cycle and that unlike any other known eukaryote, it must rely on novel or alternative set of mechanisms to carry out these fundamental processes.
Publisher: Springer Science and Business Media LLC
Date: 14-10-2021
DOI: 10.1038/S41467-021-26077-2
Abstract: Cells replicate and segregate their DNA with precision. Previous studies showed that these regulated cell-cycle processes were present in the last eukaryotic common ancestor and that their core molecular parts are conserved across eukaryotes. However, some metamonad parasites have secondarily lost components of the DNA processing and segregation apparatuses. To clarify the evolutionary history of these systems in these unusual eukaryotes, we generated a genome assembly for the free-living metamonad Carpediemonas membranifera and carried out a comparative genomics analysis. Here, we show that parasitic and free-living metamonads harbor an incomplete set of proteins for processing and segregating DNA. Unexpectedly, Carpediemonas species are further streamlined, lacking the origin recognition complex, Cdc6 and most structural kinetochore subunits. Carpediemonas species are thus the first known eukaryotes that appear to lack this suite of conserved complexes, suggesting that they likely rely on yet-to-be-discovered or alternative mechanisms to carry out these fundamental processes.
Location: United States of America
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Dayana Elizabeth Salas-Leiva.