scholarly journals [Comparative] mutagenesis of human cells in vivo and in vitro. Progress report, 1989

Author(s):  
W.G. Thilly
Keyword(s):  



1998 ◽  
Author(s):  
W.G. Thilly ◽  
K. Khrapko ◽  
X.C. Li ◽  
A. Tomita ◽  
P. Herrero
Keyword(s):  


2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Miao-Miao Zhao ◽  
Wei-Li Yang ◽  
Fang-Yuan Yang ◽  
Li Zhang ◽  
Wei-Jin Huang ◽  
...  

AbstractTo discover new drugs to combat COVID-19, an understanding of the molecular basis of SARS-CoV-2 infection is urgently needed. Here, for the first time, we report the crucial role of cathepsin L (CTSL) in patients with COVID-19. The circulating level of CTSL was elevated after SARS-CoV-2 infection and was positively correlated with disease course and severity. Correspondingly, SARS-CoV-2 pseudovirus infection increased CTSL expression in human cells in vitro and human ACE2 transgenic mice in vivo, while CTSL overexpression, in turn, enhanced pseudovirus infection in human cells. CTSL functionally cleaved the SARS-CoV-2 spike protein and enhanced virus entry, as evidenced by CTSL overexpression and knockdown in vitro and application of CTSL inhibitor drugs in vivo. Furthermore, amantadine, a licensed anti-influenza drug, significantly inhibited CTSL activity after SARS-CoV-2 pseudovirus infection and prevented infection both in vitro and in vivo. Therefore, CTSL is a promising target for new anti-COVID-19 drug development.



1993 ◽  
Vol 13 (9) ◽  
pp. 5377-5382
Author(s):  
B Datta ◽  
A M Weiner

U6 small nuclear RNA (snRNA) is the most highly conserved of the five spliceosomal snRNAs that participate in nuclear mRNA splicing. The proposal that U6 snRNA plays a key catalytic role in splicing [D. Brow and C. Guthrie, Nature (London) 337:14-15, 1989] is supported by the phylogenetic conservation of U6, the sensitivity of U6 to mutation, cross-linking of U6 to the vicinity of the 5' splice site, and genetic evidence for extensive base pairing between U2 and U6 snRNAs. We chose to mutate the phylogenetically invariant 41-ACAGAGA-47 and 53-AGC-55 sequences of human U6 because certain point mutations within the homologous regions of Saccharomyces cerevisiae U6 selectively block the first or second step of mRNA splicing. We found that both sequences are more tolerant to mutation in human cells (assayed by transient expression in vivo) than in S. cerevisiae (assayed by effects on growth or in vitro splicing). These differences may reflect different rate-limiting steps in the particular assays used or differential reliance on redundant RNA-RNA or RNA-protein interactions. The ability of mutations in U6 nucleotides A-45 and A-53 to selectively block step 2 of splicing in S. cerevisiae had previously been construed as evidence that these residues might participate directly in the second chemical step of splicing; an indirect, structural role seems more likely because the equivalent mutations have no obvious phenotype in the human transient expression assay.



2013 ◽  
Vol 288 (29) ◽  
pp. 20918-20926 ◽  
Author(s):  
Jinchuan Hu ◽  
Jun-Hyuk Choi ◽  
Shobhan Gaddameedhi ◽  
Michael G. Kemp ◽  
Joyce T. Reardon ◽  
...  

Nucleotide excision repair is the sole mechanism for removing the major UV photoproducts from genomic DNA in human cells. In vitro with human cell-free extract or purified excision repair factors, the damage is removed from naked DNA or nucleosomes in the form of 24- to 32-nucleotide-long oligomers (nominal 30-mer) by dual incisions. Whether the DNA damage is removed from chromatin in vivo in a similar manner and what the fate of the excised oligomer was has not been known previously. Here, we demonstrate that dual incisions occur in vivo identical to the in vitro reaction. Further, we show that transcription-coupled repair, which operates in the absence of the XPC protein, also generates the nominal 30-mer in UV-irradiated XP-C mutant cells. Finally, we report that the excised 30-mer is released from the chromatin in complex with the repair factors TFIIH and XPG. Taken together, our results show the congruence of in vivo and in vitro data on nucleotide excision repair in humans.



2019 ◽  
Vol 129 ◽  
pp. 256-272 ◽  
Author(s):  
T.G. Fonseca ◽  
T. Carriço ◽  
E. Fernandes ◽  
D.M.S. Abessa ◽  
A. Tavares ◽  
...  
Keyword(s):  


2012 ◽  
Vol 40 (8) ◽  
pp. e369-e374 ◽  
Author(s):  
G.F. Draenert ◽  
D.O. Huetzen ◽  
P.W. Kämmerer ◽  
V. Palarie ◽  
V. Nacu ◽  
...  


2019 ◽  
Vol 39 (21) ◽  
Author(s):  
Alexandra M. Pike ◽  
Margaret A. Strong ◽  
John Paul T. Ouyang ◽  
Carol W. Greider

ABSTRACT TIN2 is an important regulator of telomere length, and mutations in TINF2, the gene encoding TIN2, cause short-telomere syndromes. While the genetics underscore the importance of TIN2, the mechanism through which TIN2 regulates telomere length remains unclear. Here, we tested the effects of human TIN2 on telomerase activity. We identified a new isoform in human cells, TIN2M, that is expressed at levels similar to those of previously studied TIN2 isoforms. All three TIN2 isoforms localized to and maintained telomere integrity in vivo, and localization was not disrupted by telomere syndrome mutations. Using direct telomerase activity assays, we discovered that TIN2 stimulated telomerase processivity in vitro. All of the TIN2 isoforms stimulated telomerase to similar extents. Mutations in the TPP1 TEL patch abrogated this stimulation, suggesting that TIN2 functions with TPP1/POT1 to stimulate telomerase processivity. We conclude from our data and previously published work that TIN2/TPP1/POT1 is a functional shelterin subcomplex.



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