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)

Restriction endonuclease fragment length variants in mice were compared by Southern blot analysis using the cDNA probe pcXP33 for the chymotrypsin gene. The variants were detected in the restriction patterns generated by fragments from digestions with BglII, EcoRI, HindIII, Pstl, SacI, and XbaI. The set of protein phenotypes and the restriction patterns of chymotrypsin gene were examined in many laboratory strains and wild subspecies. Most laboratory strains (26 strains) are grouped into a set defined as Set 1, but only a few laboratory strains (AU/SsJ and five BALB/c sublines) are classified as belonging to Set 2. Of wild subspecies, only BRV-MPL (M. brevirostris) can be placed in Set 1, while DOM-BLG and SK/Cam (M. domesticus) belong in Set 2. The assignment of an appropriate set defined by the characteristics of the chymotrypsin gene has also been investigated in M. musculus, two Chinese subspecies, M. yamashinai, M. molossinus, and M. castaneus, and the evolutionary relationship between laboratory mice and various subspecies of Mus has been examined.
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PMID:Evolutionary relationships between laboratory mice and subspecies of Mus musculus based on the restriction fragment length variants of the chymotrypsin gene at the Prt-2 locus. 256 17

The organization of mouse immunoglobulin heavy chain genes has been investigated by hybridization with cloned mu and alpha cDNA probes. Restriction endonuclease fragments bearing mu and alpha constant region genes and two types of variable region (VH) genes were compared in BALB/c embryos, liver and nine plasmacytomas synthesizing IgM, IgA, IgG1, IgG2a, IgG2b and IgG3. Embryo DNA was found to contain a single copy of the C mu gene per haploid genome. In contrast, one VH probe (HPC 76) detected at least six related VH genes, while the other (S107) detected a separate set of at least four genes, indicating that the germline contains distinct sets of multiple related VH genes. Most VH genes within the two subsets remained in germline context in different plasmacytomas, providing no evidence for somatic reassortment of VH genes. One plasmacytoma was devoid of specific VH genes, including some related to the expressed VH sequence. This may mean that the translocation event creating an active heavy chain gene involves deletion of the DNA between the expressed VH and CH sequences. The context of C mu sequences in DNA from a plasmacytoma secreting IgM differed from that in embryo DNA, as did C alpha sequences in two IgA- and several IgG-secreting plasmacytomas. Unlike heavy chain expression, rearrangement was not confined to one allele and often took different forms within a single cell line, presumably varying on different homologous chromosomes. Each rearrangement, whether resulting in an active C gene or not, appeared to change sequences upstream but not downstream from the CH gene. Significantly, the eight IgG and IgA plasmacytomas examined had undergone deletions of at least half and often all C mu sequences while retaining the embryo level of C alpha sequences. Hence a deletion mechanism may be responsible for the switch in expression from one CH gene to another which occurs during differentiation of a lymphocyte clone.
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PMID:Deletions are associated with somatic rearrangement of immunoglobulin heavy chain genes. 676 10

We studied the role of proteases in apoptosis using a cell-free system prepared from a human leukemia cell line. HL60 cells are p53 null and extremely sensitive to a variety of apoptotic stimuli including DNA damage induced by the topoisomerase I inhibitor, camptothecin. We measured DNA fragmentation induced in isolated nuclei by cytosolic extracts using a filter elution assay. Cytosol from camptothecin-treated HL60 cells induced internucleosomal DNA fragmentation in nuclei from untreated cells. This fragmentation was suppressed by serine protease inhibitors. Serine proteases (trypsin, endoproteinase Glu-C, chymotrypsin A, and proteinase K) and papain by themselves induced DNA fragmentation in naive nuclei. This effect was enhanced in the presence of cytosol from untreated cells. Cysteine protease inhibitors (E-64, leupeptin, Ac-YVAD-CHO [ICE inhibitor]) did not affect camptothecin-induced DNA fragmentation. The apopain/Yama inhibitor, Ac-DEVD-CHO, and the proteasome inhibitor, MG-132, were also inactive both in the cell-free system and in whole cells. Interleukin-1 beta converting enzyme (ICE) or human immunodeficiency virus protease failed to induce DNA fragmentation in naive nuclei. Together, these results suggest that DNA damage activates serine protease(s) which in turn activate(s) nuclear endonuclease(s) during apoptosis in HL60 cells.
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PMID:DNA fragmentation induced by protease activation in p53-null human leukemia HL60 cells undergoing apoptosis following treatment with the topoisomerase I inhibitor camptothecin: cell-free system studies. 880 33

A target sequence-specific DNA binding region of the restriction endonuclease Sso II was identified by photocross-linking with an oligodeoxynucleotide duplex which was substituted with 5-iododeoxy-uridine (5-IdU) at the central position of the Sso II recognition site (CCNGG). For this purpose the Sso II-DNA complex was irradiated with a helium/cadmium laser (325 nm). The cross-linking yield obtained was approximately 50%. In the presence of excess unmodified oligodeoxynucleotide or with oligode-oxynucleotides substituted with 5-IdU elsewhere, no cross-linking was observed, indicating the specificity of the cross-linking reaction. The cross-linked Sso II-oligodeoxynucleotide complex was digested with chymotrypsin, a cross-linked peptide-oligodeoxy-nucleotide complex isolated and the site of cross-linking identified by Edman sequencing to be Trp61. In line with this identification is the finding that the W61A variant cannot be cross-linked with the IdU-substituted oligodeoxynucleotide, shows a decrease in affinity towards DNA and is inactive in cleavage. It is concluded that the region around Trp61 is involved in specific binding of Sso II to its DNA substrate.
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PMID:Identification of a base-specific contact between the restriction endonuclease SsoII and its recognition sequence by photocross-linking. 1066 47