Faculty Opinions recommendation of Complementary base pairing and the origin of substitution mutations.

2014 ◽  
Author(s):  
Eric Westhof
Keyword(s):  
Base Pairing ◽  
Substitution Mutations

Complementary base pairing and the origin of substitution mutations

Nature ◽  
1976 ◽  
Vol 263 (5575) ◽  
pp. 285-289 ◽  
Author(s):  
Michael D. Topal ◽  
Jacques R. Fresco
Keyword(s):  
Base Pairing ◽  
Substitution Mutations

scholarly journals Template-directed base pairing of 2-chloro-2'-deoxyadenosine catalyzed by AMV reverse transcriptase.

1998 ◽  
Vol 45 (2) ◽  
pp. 587-593 ◽  
Author(s):  
A M Bukowska-Maciejewska ◽  
J T Kuśmierek
Keyword(s):  
Binding Energy ◽  
Reverse Transcriptase ◽  
Kinetic Parameters ◽  
Active Site ◽  
Base Substitution ◽  
Base Pairing ◽  
Lymphoid Malignancies ◽  
Order Of Magnitude ◽  
The Difference ◽  
Substitution Mutations

2-Chloro-2'-deoxyadenine (2CldA) is used for treatment of several lymphoid malignancies. Since this drug is incorporated into DNA, we have undertaken studies on base pairing of 2-chloroadenine (2ClA). 2CldA phosphoramidite was synthesized and used for preparation of 25-mer templates with 2ClA located at site 21 from the 3'-end. Kinetic parameters (Km and Vmax) for the incorporation of deoxynucleoside-5'-triphosphates by AMV reverse transcriptase opposite the 2ClA template, as well as for the extension of 2ClA.T pair, were determined. The efficiency (Vmax/Km) of incorporation of dGTP, dCTP, and dATP opposite 2ClA is at least one order of magnitude lower than opposite unmodified A. The efficiency of incorporation of dTTP opposite 2ClA is about 30-fold lower than opposite A and extension of 2ClA.T pair is 3-fold lower than of A.T pair. From the analysis of the parameters of dTTP incorporation we conclude that formation of 2ClA.T pair is thermodynamically, but not kinetically controlled. The difference in binding energy (deltadeltaG) between 2ClA.T and A.T pairs in the environment of the polymerase active site is 2 kcal/mol. Our results indicate that the presence of 2ClA in DNA slows down replication, but does not lead to base-substitution mutations.

scholarly journals Direct Interactions with Nascent Transcripts Is Potentially a Common Targeting Mechanism of Long Non-Coding RNAs

Genes ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1483
Author(s):  
Ivan Antonov ◽  
Yulia Medvedeva
Keyword(s):  
Target Genes ◽  
Regulation Of Gene Expression ◽  
Pilot Project ◽  
Base Pairing ◽  
Nascent Transcript ◽  
Active Transcription ◽  
Wet Lab ◽  
In Trans ◽  
Non Coding Rnas ◽  
Nascent Transcripts

Although thousands of mammalian long non-coding RNAs (lncRNAs) have been reported in the last decade, their functional annotation remains limited. A wet-lab approach to detect functions of a novel lncRNA usually includes its knockdown followed by RNA sequencing and identification of the deferentially expressed genes. However, identification of the molecular mechanism(s) used by the lncRNA to regulate its targets frequently becomes a challenge. Previously, we developed the ASSA algorithm that detects statistically significant inter-molecular RNA-RNA interactions. Here we designed a workflow that uses ASSA predictions to estimate the ability of an lncRNA to function via direct base pairing with the target transcripts (co- or post-transcriptionally). The workflow was applied to 300+ lncRNA knockdown experiments from the FANTOM6 pilot project producing statistically significant predictions for 71 unique lncRNAs (104 knockdowns). Surprisingly, the majority of these lncRNAs were likely to function co-transcriptionally, i.e., hybridize with the nascent transcripts of the target genes. Moreover, a number of the obtained predictions were supported by independent iMARGI experimental data on co-localization of lncRNA and chromatin. We detected an evolutionarily conserved lncRNA CHASERR (AC013394.2 or LINC01578) that could regulate target genes co-transcriptionally via interaction with a nascent transcript by directing CHD2 helicase. The obtained results suggested that this nuclear lncRNA may be able to activate expression of the target genes in trans by base-pairing with the nascent transcripts and directing the CHD2 helicase to the regulated promoters leading to open the chromatin and active transcription. Our study highlights the possible importance of base-pairing between nuclear lncRNAs and nascent transcripts for the regulation of gene expression.

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