| 1. |
- Barandun, Jonas, et al.
(författare)
-
Evolutionary compaction and adaptation visualized by the structure of the dormant microsporidian ribosome
- 2019
-
Ingår i: Nature Microbiology. - : Nature Publishing Group. - 2058-5276. ; 4:11, s. 1798-1804
-
Tidskriftsartikel (refereegranskat)abstract
- Microsporidia are eukaryotic parasites that infect essentially all animal species, including many of agricultural importance(1-3), and are significant opportunistic parasites of humane. They are characterized by having a specialized infection apparatus, an obligate intracellular lifestyles(5), rudimentary mitochondria and the smallest known eukaryotic genomess(5-7). Extreme genome compaction led to minimal gene sizes affecting even conserved ancient complexes such as the ribosomes(8-10). In the present study, the cryo-electron microscopy structure of the ribosome from the microsporidium Vairimorpha necatrix is presented, which illustrates how genome compaction has resulted in the smallest known eukaryotic cytoplasmic ribosome. Selection pressure led to the loss of two ribosomal proteins and removal of essentially all eukaryote-specific ribosomal RNA (rRNA) expansion segments, reducing the rRNA to a functionally conserved core. The structure highlights how one microsporidia-specific and several repurposed existing ribosomal proteins compensate for the extensive rRNA reduction. The microsporidian ribosome is kept in an inactive state by two previously uncharacterized dormancy factors that specifically target the functionally important E-site, P-site and polypeptide exit tunnel. The present study illustrates the distinct effects of evolutionary pressure on RNA and proteincoding genes, provides a mechanism for ribosome inhibition and can serve as a structural basis for the development of inhibitors against microsporidian parasites.
|
|
| 2. |
- Russell, Andrew J.C., et al.
(författare)
-
Regulators of male and female sexual development are critical for the transmission of a malaria parasite
- 2023
-
Ingår i: Cell Host and Microbe. - : Cell Press. - 1931-3128 .- 1934-6069. ; 31:2, s. 305-319.e10
-
Tidskriftsartikel (refereegranskat)abstract
- Malaria transmission to mosquitoes requires a developmental switch in asexually dividing blood-stage parasites to sexual reproduction. In Plasmodium berghei, the transcription factor AP2-G is required and sufficient for this switch, but how a particular sex is determined in a haploid parasite remains unknown. Using a global screen of barcoded mutants, we here identify genes essential for the formation of either male or female sexual forms and validate their importance for transmission. High-resolution single-cell transcriptomics of ten mutant parasites portrays the developmental bifurcation and reveals a regulatory cascade of putative gene functions in the determination and subsequent differentiation of each sex. A male-determining gene with a LOTUS/OST-HTH domain as well as the protein interactors of a female-determining zinc-finger protein indicate that germ-granule-like ribonucleoprotein complexes complement transcriptional processes in the regulation of both male and female development of a malaria parasite.
|
|
