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)

A physical technique known as two-dimensional S1 nuclease heteroduplex mapping has been applied to genomic DNA from the Gram-negative coccus Neisseria gonorrhoeae. This has resulted in the detection of two novel types of repetitive sequences. The first type is a repetitive sequence family of 152 base pairs (bp), whose ends are composed of inverted repeats of 26 bp. There are approximately 20 copies of this sequence, in both N. gonorrhoeae and Neisseria meningitidis (Correia, F., Inouye, S., and Inouye, M. (1986) J. Bacteriol. 167, 1009-1011). The second type of sequence is a 1443-bp duplication in the N. gonorrhoeae genome. The two classes of sequence are linked positionally. Each copy of the long duplicated sequence is adjacent to a member of the 152-bp repetitive sequence. In one instance two copies of the 152-bp repetitive sequence are separated by a 436-bp central region and are in an inverted orientation with respect to one another, resembling a compound transposable element.
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PMID:A family of small repeated elements with some transposon-like properties in the genome of Neisseria gonorrhoeae. 284 23

A single-stranded DNA probe complementary to chicken type II procollagen mRNA has been used to quantitate levels of that mRNA present in chicken limb mesenchyme during cartilage differentiation. Excess labeled probe prepared from a cDNA template cloned in M13mp9 was hybridized to completion to increasing amounts of total RNA and assayed by protection from S1 nuclease digestion. Estimates of the absolute levels of type II procollagen RNA were determined using the M13mp9 template containing the coding strand as a standard. RNA complementary to the probe increased from 20 copies per diploid genome in stage 24 limb to approximately 2000 copies per diploid genome in stage 24 limb mesenchyme which had differentiated to cartilage in culture. Similar levels were found in cartilage from stage 31 limb. Sternal cartilage from 17-day embryos contained approximately 10,000 copies per diploid genome suggesting that the level of expression of this gene is different in limb growth cartilage compared with sternal cartilage. Low but detectable levels of RNA complementary to the probe were observed in limb at stages 20-24. Since a large fraction of the type II procollagen RNA in these early limbs is associated with polysomes, the type II procollagen gene appears to be expressed at a low level prior to phenotypic differentiation and prior to the accumulation of immunologically detectable levels of type II collagen.
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PMID:Quantitation of type II procollagen mRNA levels during chick limb cartilage differentiation. 383 85

A repeated DNA sequence in the genome of Bordetella parapertussis was identified by means of heteroduplex formation and S1 nuclease treatment. Cloning and sequencing of the repeated sequence, revealed that it comprised 1306 basepairs, contained inverted repeats at its termini, and two large open reading frames. This insertion sequence element was designated IS1001, and was found in about 20 copies in 10 B. parapertussis strains analyzed. Identical hybridization patterns were observed in B. parapertussis when IS1001 was used as a probe. B. pertussis strains did not hybridize to IS1001.
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PMID:Isolation of a repeated sequence from the genome of Bordetella parapertussis with characteristics of an insertion sequence element. 839 66

Two distinct families of repetitive DNA elements (1.4 and 1.2 kb) were identified from S1 nuclease-treated genomic DNA of four strains of Thiobacillus ferrooxidans. The 1.4-kb fragment hybridized with IST2, an insertion sequence of T. ferrooxidans. The 1.2-kb fragment was cloned and sequenced. The sequence (IST445), 1219 bp in length, with features characteristic of an insertion element, has a terminal inverted repeat of 8 bp, which can be further extended to 23 or 48 bp with 9 and 26 mismatches, respectively. It displays 54.4% identity in 967 nucleotides of overlap with ISAE1 of Alcaligenes eutrophus. The IST445 contains three open reading frames which have codon usage almost similar to 56 different coding genes of T. ferrooxidans. In Southern blots of restricted genomic DNAs probed with IST445, each of the several strains of T. ferrooxidans gives a distinctive fingerprint. IST445 is present in the range of 10-20 copies per genome in the four strains studied.
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PMID:Cloning and characterization of a high-copy-number novel insertion sequence from chemolithotrophic Thiobacillus ferrooxidans. 933 70