Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.30.2 (endonuclease)
 18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The restriction endonuclease BSu, an isoschizomer of the enzyme HaeIII, cleaves human DNA to yield classes of fragments that are characteristic of the DNA of individuals having a Y chromosome. The fragments concerned are therefore diagnostic of the presence of Y-chromosome DNA and have been studied here with the intention of confirming the origin of various translocations thought, on other grounds, to involve the Y. The absence of the fragments from DNA of a case exhibiting absence of the fluorecent region of Yq suggests that the DNA concerned maps predominantly to Yq. Normal gender in the absence of the BSu fragments indicates that they do not function in sex determination.
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PMID:BSu restriction of DNA from cases exhibiting sex-chromosome abnormalities. 64 90

The heterogeneity of constitutive heterochromatin in two domestic pigs has been studied by restriction endonuclease AluI banding, CA3/DA/DAPI banding and C-banding techniques. The results show that the centromere constitutive heterochromatin can be subdivided into three types, which located in different chromosomes. It is found that there is correspondence between No. 13--18 chromosomes in pigs and No. 1, 9, 16, Y chromosome in human by comparing the banding patterns of AluI and CA3/DA/DAPI. Therefore, it is revealed that satellite DNAs in constitutive heterochromatin of chromosomes mentioned above are similar.
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PMID:[Expression of constitutive heterochromatin by AluI restriction endonuclease treatment and CA3/DA/DAPI staining of domestic pig chromosome]. 226 47

We have used endonuclease treatment in situ, followed by Giemsa or ethidium bromide staining, for mapping repetitive sequences on the chromosomes of the flesh fly Sarcophaga bullata and thus for studying extrachromosomal DNA granules in this species. All three restriction enzymes employed (HaeIII, A1uI and HindIII) show the same cytological effects, except for a single interstitial band. In both polytene and mitotic chromosomes, chromatin resistant to these endonucleases presumably includes at least three endonucleases presumably includes at least three previously unrecognized buoyant density satellites (1.663, 1.670 and 1.692 g ml-1 in neutral CsCl), and is predominantly localized in the pericentric regions of all five autosomes. Mitotic treated chromosomes show that the entire rod-shaped X chromosome, but no part of the dot-like Y chromosome, consists of endonuclease-resistant chromatin. The most unusual heterochromatic component of polytene nuclei in this species, the 'extrachromosomal DNA granules', are also entirely resistant to digestion with endonucleases. We think that these DNA granules represent dispersed X chromatin and not, as previously assumed, extruded autosomal heterochromatin.
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PMID:Characterization and origin of extrachromosomal DNA granules in Sarcophaga bullata. 283 6

Four experiments evaluated the sensitivity and specificity of molecular techniques to detect human Y chromosome deoxyribonucleic acid. In experiment I, electrophoretic separation of normal male deoxyribonucleic acid fragments after digestion with endonuclease Hae III revealed two male-specific bands of 3.4 and 2.1 kilobase (kb). These bands were not visible if the fraction of male deoxyribonucleic acid in mixed samples was less than 0.3. In experiment II, by means of a repetitive copy Y deoxyribonucleic acid probe (pS4) mapped to Yq12, a male-specific 2.3 kb band was detectable in mixtures of 2.5 ng of male deoxyribonucleic acid and 997.5 ng of 45,X female deoxyribonucleic acid. In experiment III, hybridization with the pS4 probe was performed on the deoxyribonucleic acid of 20 subjects with a normal or a variant Y chromosome. In experiment IV, deoxyribonucleic acid from the same subjects was hybridized to a single copy probe (4B-2) mapped to the Yq11 region. Deoxyribonucleic acid from category A subjects (n = 8) with cytologically normal Y chromosomes hybridized to both deoxyribonucleic acid probes. Deoxyribonucleic acid from category B subjects (n = 2), including a variant Y chromosome that was negative for Q-banding but positive for C-bands, hybridized with the distal pS4 and proximal 4B-2 probes. Deoxyribonucleic acid from category C subjects (n = 10) with variant Y chromosomes uniformly negative for Q- and C-bands, did not hybridize with the pS4 probe. Deoxyribonucleic acid from three of the 10 category C subjects did hybridize to the more proximal sequence-detecting 4B-2 probe. Deoxyribonucleic acid from the remaining seven subjects in category C did not hybridize with either of the deoxyribonucleic acid probes.
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PMID:Use of two different deoxyribonucleic acid probes to detect Y chromosome deoxyribonucleic acid in subjects with normal and altered Y chromosomes. 300 57

The heterochromatin in Indian muntjac (Muntiacus muntjak) is located at the periphery of primary constrictions of all the chromosomes. The X chromosome contains significantly larger amounts of heterochromatin than the rest of the complement by C-banding technique. However, the small portion of C-band region was found to be resistant by restriction endonuclease HaeIII (5'...GG decreases CC...3') and was clearly visible on the nucleus. Therefore, the position of this large heterochromatic segment is examined at somatic metaphases. The distribution of the heterochromatin of the X chromosome observed in Indian muntjac is contrary to the general pattern observed in other species, i.e., the chromosomes consisting greater amount of heterochromatin are located more peripherally than those with lesser amount. However, the smaller Y chromosome (Y1) is frequently found at the periphery. The present findings suggest that the role of heterochromatin organization in the nucleus vary between different heterochromatic segments of the same species and vary from species to species.
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PMID:Heterochromatin organization in the nucleus of Indian muntjac (Muntiacus muntjak). 375 10

We have used two repeated DNA fragments (3.4 and 2.1 kb) released from Y chromosome DNA by digestion with the restriction endonuclease Hae III to analyze potential Y chromosome/autosome translocations. Two female patients were studied who each had an abnormal chromosome 22 with extra quinacrine fluorescent material on the short arm. The origin of the 22p+ chromosomes was uncertain after standard cytologic examinations. Analysis of one patient's DNA with the Y-specific repeated DNA probes revealed the presence of both the 3.4 and 2.1kb Y-specific fragments. Thus, in this patient, the additional material was from the Y chromosome. Analysis of the second patient's DNA for Y-specific repeated DNA was negative, indicating that the extra chromosomal segment was not from the long arm of the Y chromosome. These two cases demonstrate that repeated DNA can distinguish between similar appearing aberrant chromosomes and may be useful in karyotypic and prenatal diagnosis.
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PMID:Use of repetitive DNA for diagnosis of chromosomal rearrangements. 631 27

Prenatal diagnosis by chorion biopsy in the first trimester of pregnancy has advantages over second trimester amniocentesis because diagnosis can be achieved at 9-12 weeks gestation, reducing prenatal anxiety and avoiding the trauma of late abortion. DNA can be prepared from chorionic villus biopsies in sufficient quantity and purity for use in prenatal diagnosis systems using specific DNA probes hybridised to restriction endonuclease digests. DNA probes derived from the Y chromosome have been used to determine fetal sex. The use of such probes means that the chromosomal sex of the fetus can be identified more quickly than by chromosome preparation and more accurately than by sex chromatin staining, and has the additional advantage that the same DNA preparation can be used for other diagnostic tests. A dot hybridisation method has been successfully used to provide even more rapid results than conventional hybridisation to Southern blots of restriction endonuclease digests. There is a risk that Y chromosome-specific DNA probes for sex determination may be subject to error if the parents have extreme Y chromosome variants such as a small or non-fluorescent Y or a Y autosome chromosome translocation. The precise extent to which such chromosome variants may lead to error has been investigated. Even extreme Y chromosome variants totally lacking fluorescence were identified as male by the cloned probes used. However, Y autosome translocations carried by females could cause error if not identified in the parents. The value of the probes has been confirmed provided that parental chromosomes and DNA are examined in parallel with the chorionic biopsy material.
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PMID:The use of cloned Y chromosome-specific DNA probes for fetal sex determination in first trimester prenatal diagnosis. 653 98

A human X chromosome specific phage library has been used as a source of X-specific genomic DNA clones which hybridize with cellular RNA. Random cDNA clones were mapped for X chromosome sequence localization and 8 were identified as hybridizing to X chromosome Hind III fragments. All eight also hybridized with autosomal Hind III fragments. The X chromosome genomic sequences corresponding to two of these cDNA clones were isolated from a phage library constructed with the Hind III endonuclease digest products of X enriched DNA. One genomic DNA segment, localized to the short area of the X, shared sequence homology with at least one region of the human Y chromosome. The methodology developed represents a rapid means to obtain a specific genomic DNA clone from a single chromosome when multiple different genomic loci homologous to an expressed DNA sequence exist.
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PMID:Identification and isolation of transcribed human X chromosome DNA sequences. 668 68

Variants in structure and content of the human Y chromosome were investigated by cytogenetic methods and by restriction endonuclease analysis. It is shown that most or all of the 2.1-kb male-specific reiterated sequence is located in the distal part of the brightly fluorescing heterochromatin.
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PMID:Regional assignment of a 2.1-kb repetitive sequence to the distal part of the human Y heterochromatin. 745 Jul 68

Nine newly described single-copy and low-copy-number genomic DNA sequences isolated from a flow-sorted human Y chromosome library were mapped to regions of the human Y chromosome and were hybridized to Southern blots of male and female great ape genomic DNAs (Gorilla gorilla, Pan troglodytes, Pongo pygmaeus). Eight of the nine sequences mapped to the euchromatic Y long arm (Yq) in humans, and the ninth mapped to the short arm or pericentromeric region. All nine of the newly identified sequences and two additional human Yq sequences hybridized to restriction fragments in male but not female genomic DNA from the great apes, indicating Y chromosome localization. Seven of these 11 human Yq sequences hybridized to similarly-sized restriction endonuclease fragments in all the great ape species analyzed. The five human sequences that mapped to the most distal subregion of Yq (deletion of which region is associated with spermatogenic failure in humans) were hybridized to Southern blots generated by pulsed-field gel electrophoresis. These sequences define a region of approximately 1 Mb on human Yq in which HpaII tiny fragment (HTF) islands appear to be absent. The conservation of these human Yq sequences on great ape Y chromosomes indicates a greater stability in this region of the Y than has been previously described for most anonymous human Y chromosomal sequences. The stability of these sequences on great ape Y chromosomes seems remarkable given that this region of the Y does not undergo meiotic recombination and the sequences do not appear to encode genes for which positive selection might occur.
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PMID:Conservation of human Y chromosome sequences among male great apes: implications for the evolution of Y chromosomes. 806 69


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