Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.30.1 (S1 nuclease)
 3,660 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

When propagated on arl strains (a subclass of Escherichia coli hyper-rec mutants), lambda "Red-" duplication phages accumulated an enhanced potential for recombination. The physical properties of the recombinogenic phages thus obtained ("Arl-" phages) were similar to those of phages grown on arl+ bacteria. However, Arl- phage DNA was cleaved by endonuclease S1 under conditions such that the nuclease is specific for single-stranded DNA;DNA from control phages was S1-resistant. The number of S1 sites (defined by the apparent decrease in single-strand molecular weight) reached a maximum (seven to nine sites per strand of lambda DNA) after five or six rounds of growth on arl bacteria. Similarly, the recombinogenicity of Arl- phages reached a limiting value (recombination frequency, 15%) that was 5 times that of Arl+ phages. Recombinogenicity and S1 susceptibility were accumulated concomitantly during growth on arl+ bacteria. If all increased recombination occurred at the S1 sites, then these regions (about 40 bases each) were about 300 times as recombinogenic as normal DNA regions of the same size, and 1.5 times as recombinogenic as UV-induced lesions. Chromosomal DNA and plasmid DNA (pBR322) from arl cells were more susceptible to nuclease S1 than was DNA from arl+ bacteria. Analysis of the cleavage products suggests that the S1 sites on Arl- lambda phage DNA are located randomly.
 ...
PMID:DNA from recombinogenic lambda bacteriophages generated by arl mutant of Escherichia coli is cleaved by single-strand-specific endonuclease S1. 388 50

A mutagenic steroidal derivative (3 beta-Acetoxy-5 alpha-Cholestano[6 alpha,5-d']1'-3'oxathiolane-2' thione) structurally related to cholesterol caused strand scission and induced nicks in calf thymus, supercoiled pBR322 and single stranded M13 mp8 phage DNAs. S1 nuclease hydrolysis, reaction with pBR322 and M13 phage DNA as well as treatment of E. coil mutant strains and phage was used to evaluate the effect of test steroid on the DNA molecule. The strand scission/nicking of DNA by the test steroid was enhanced by some metal ions, especially the Cu(II). Scavengers of active oxygen radical species significantly inhibited the S1 nuclease hydrolysis by the test steroid indicating the major role of active oxygen species in DNA strand scission and nicking. The steroid brought about the DNA degradation even in the absence of S1 nuclease. There was an appreciable reduction in the survival of steroid treated polA and lig mutants of E. coli K12 compared to the wild type strain. Phage on steroid treatment also lost its plaque forming units (P.F.U.) which was more pronounced in the polA and rec A background.
 ...
PMID:Steroid induced single strand breaks in DNA mediated by active oxygen species and its biological consequences. 848 66