scholarly journals Inactivation of the riboswitch-controlled GMP synthase GuaA in Clostridioides difficile is associated with severe growth defects and poor infectivity in a mouse model of infection

RNA Biology ◽  
2021 ◽  
pp. 1-12
Author(s):  
Erich Smith-Peter ◽  
David Lalonde Séguin ◽  
Émilie St-Pierre ◽  
Ognjen Sekulovic ◽  
Simon Jeanneau ◽  
...  
2019 ◽  
Vol 70 (20) ◽  
pp. 5575-5590 ◽  
Author(s):  
Shan-Shan Wei ◽  
Wei-Tao Niu ◽  
Xiao-Ting Zhai ◽  
Wei-Qian Liang ◽  
Meng Xu ◽  
...  

Abstract The 70 kDa heat shock proteins function as molecular chaperones and are involved in diverse cellular processes. However, the functions of the plant mitochondrial HSP70s (mtHSC70s) remain unclear. Severe growth defects were observed in the Arabidopsis thaliana mtHSC70-1 knockout lines, mthsc70-1a and mthsc70-1b. Conversely, the introduction of the mtHSC70-1 gene into the mthsc70-1a background fully reversed the phenotypes, indicating that mtHSC70-1 is essential for plant growth. The loss of mtHSC70-1 functions resulted in abnormal mitochondria and alterations to respiration because of an inhibition of the cytochrome c oxidase (COX) pathway and the activation of the alternative respiratory pathway. Defects in COX assembly were observed in the mtHSC70-1 knockout lines, leading to decreased COX activity. The mtHSC70-1 knockout plants have increased levels of reactive oxygen species (ROS). The introduction of the Mn-superoxide dismutase 1 (MSD1) or the catalase 1 (CAT1) gene into the mthsc70-1a plants decreased ROS levels, reduced the expression of alternative oxidase, and partially rescued growth. Taken together, our data suggest that mtHSC70-1 plays important roles in the establishment of COX-dependent respiration.


PLoS ONE ◽  
2009 ◽  
Vol 4 (12) ◽  
pp. e8506 ◽  
Author(s):  
João V. Cordeiro ◽  
Susana Guerra ◽  
Yoshiki Arakawa ◽  
Mark P. Dodding ◽  
Mariano Esteban ◽  
...  

2014 ◽  
Vol 93 (1) ◽  
pp. 65-79 ◽  
Author(s):  
Jun Yang ◽  
Yinlan Bai ◽  
Yang Zhang ◽  
Vincent D. Gabrielle ◽  
Lei Jin ◽  
...  

2002 ◽  
Vol 70 (3) ◽  
pp. 1631-1634 ◽  
Author(s):  
Stephan Köhler ◽  
Euloge Ekaza ◽  
Jean-Yves Paquet ◽  
Karl Walravens ◽  
Jacques Teyssier ◽  
...  

ABSTRACT The heat shock protein DnaK is essential for intramacrophagic replication of Brucella suis. The replacement of the stress-inducible, native dnaK promoter of B. suis by the promoter of the constitutively expressed bla gene resulted in temperature-independent synthesis of DnaK. In contrast to a dnaK null mutant, this strain grew at 37°C, with a thermal cutoff at 39°C. However, the constitutive dnaK mutant, which showed high sensitivity to H2O2-mediated stress, failed to multiply in murine macrophage-like cells and was rapidly eliminated in a mouse model of infection, adding strong arguments to our hypothesis that stress-mediated and heat shock promoter-dependent induction of dnaK is a crucial event in the intracellular replication of B. suis.


2008 ◽  
Vol 28 (10) ◽  
pp. 3177-3189 ◽  
Author(s):  
Atsushi Sawada ◽  
Hiroshi Kiyonari ◽  
Kanako Ukita ◽  
Noriyuki Nishioka ◽  
Yu Imuta ◽  
...  

ABSTRACT Four members of the TEAD/TEF family of transcription factors are expressed widely in mouse embryos and adult tissues. Although in vitro studies have suggested various roles for TEAD proteins, their in vivo functions remain poorly understood. Here we examined the role of Tead genes by generating mouse mutants for Tead1 and Tead2. Tead2 −/− mice appeared normal, but Tead1 −/−; Tead2 −/− embryos died at embryonic day 9.5 (E9.5) with severe growth defects and morphological abnormalities. At E8.5, Tead1 −/−; Tead2 −/− embryos were already small and lacked characteristic structures such as a closed neural tube, a notochord, and somites. Despite these overt abnormalities, differentiation and patterning of the neural plate and endoderm were relatively normal. In contrast, the paraxial mesoderm and lateral plate mesoderm were displaced laterally, and a differentiated notochord was not maintained. These abnormalities and defects in yolk sac vasculature organization resemble those of mutants for Yap, which encodes a coactivator of TEAD proteins. Moreover, we demonstrated genetic interactions between Tead1 and Tead2 and Yap. Finally, Tead1 −/−; Tead2 −/− embryos showed reduced cell proliferation and increased apoptosis. These results suggest that Tead1 and Tead2 are functionally redundant, use YAP as a major coactivator, and support notochord maintenance as well as cell proliferation and survival in mouse development.


2010 ◽  
Vol 48 (5) ◽  
pp. 191-195 ◽  
Author(s):  
Petra C.F. Oyston ◽  
Gabriela Mellado-Sanchez ◽  
Marcela F. Pasetti ◽  
James P. Nataro ◽  
Richard W. Titball ◽  
...  

2007 ◽  
Vol 51 (6) ◽  
pp. 2048-2052 ◽  
Author(s):  
Daniel R. Gentry ◽  
Stephen F. Rittenhouse ◽  
Lynn McCloskey ◽  
David J. Holmes

ABSTRACT To assess their effects on susceptibility to retapamulin in Staphylococcus aureus, first-, second-, and third-step mutants with elevated MICs to tiamulin and other investigational pleuromutilin compounds were isolated and characterized through exposure to high drug concentrations. All first- and second-step mutations were in rplC, encoding ribosomal protein L3. Most third-step mutants acquired a third mutation in rplC. While first- and second-step mutations did cause an elevation in tiamulin and retapamulin MICs, a significant decrease in activity was not seen until a third mutation was acquired. All third-step mutants exhibited severe growth defects, and faster-growing variants arose at a high frequency from most isolates. These faster-growing variants were found to be more susceptible to pleuromutilins. In the case of a mutant with three alterations in rplC, the fast-growing variants acquired an additional mutation in rplC. In the case of fast-growing variants of isolates with two mutations in rplC and at least one mutation at an unmapped locus, one of the two rplC mutations reverted to wild type. These data indicate that mutations in rplC that lead to pleuromutilin resistance have a direct, negative effect on fitness. While reduction in activity of retapamulin against S. aureus can be seen through mutations in rplC, it is likely that target-specific resistance to retapamulin will be slow to emerge due to the need for three mutations for a significant effect on activity and the fitness cost of each mutational step.


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