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

We have recently reported that mammalian sperm DNA, the most highly condensed and functionally inert eukaryotic DNA, is organized into DNA loop domains attached at their bases to a sperm nuclear matrix (Chromosoma, 98: 153, 1989). We report here the specific arrangement of genes within the sperm loop domains by measuring the proximity of six hamster genes to the sperm nuclear matrix. After restriction endonuclease treatment of sperm nuclear matrices, five genes were clearly not associated with the sperm nuclear matrix and only one, alpha A-crystallin, was within 2 Kb of the matrix. This suggests that sperm DNA is organized in a specific manner in relation to the sperm matrix.
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PMID:Specific organization of genes in relation to the sperm nuclear matrix. 217 76

To map precisely the mutation locus of eye lens obsolescence (Elo) on mouse chromosome 1, subsequent linkage analysis was achieved using backcross mating between 129/SvSl-Elo (Elo/+) and 129/SvSl (+/+). Mouse genomic DNAs from 17 strains including the Elo mutant mouse were first digested with several restriction enzymes and analyzed by hybridization using gamma 2- and gamma 4-crystallin cDNAs as probes. Restriction endonuclease DraI showed distinct RFLP patterns in both cases. When gamma 2-crystallin cDNA was used as the probe, two strong bands were observed at 4.0 and 2.4 kb in the majority of strains, but the former fragment shifted to the 3.4-kb position in 129/SvSl-Elo (Elo/Elo) and CFO. The polymorphism between 4.0- and 3.4-kb fragments corresponded to the gamma 1-crystallin locus (Cryg-1), and that of the 2.4-kb one, to the gamma 2-crystallin locus (Cryg-2). Mouse DNAs were also analyzed by hybridization using gamma 4-crystallin cDNA (Cryg-4). In this case, 3.4- and 3.0-kb fragments were observed in Elo and wild-type mice, respectively. The backcross offsprings were analyzed with respect to Elo, Idh-1, Cryg-1, and Cryg-4 loci. Among 223 mice analyzed, recombination between Elo and Idh-1 loci was observed in three offsprings; and that between Cryg-1 or Cryg-4 and Idh-1 loci, in one offspring. No recombination occurred between Cryg-1 and Cryg-4 alleles.
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PMID:Linkage analysis of the mutation locus in the eye lens obsolescence (Elo) mouse. 257 75

The methylation state of DNA from human colon tissue displaying neoplastic growth was determined by means of restriction endonuclease analysis. When compared to DNA from adjacent normal tissue, DNA from both benign colon polyps and malignant carcinomas was substantially hypomethylated. With the use of probes for growth hormone, gamma-globin, alpha-chorionic gonadotropin, and gamma-crystallin, methylation changes were detected in all 23 neoplastic growths examined. Benign polyps were hypomethylated to a degree similar to that in malignant tissue. These results indicate that hypomethylation is a consistent biochemical characteristic of human colonic tumors and is an alteration in the DNA that precedes malignancy.
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PMID:Hypomethylation of DNA from benign and malignant human colon neoplasms. 257 35

Restriction endonuclease mapping and electron microscopy established that there are at least two nonallelic delta-crystallin genes in the chicken. The structure of a complete delta-crystallin gene has been deduced by analysis of five cloned fragments from the chicken genome. Fifteen intervening sequences compose approximately 80% of this gene; the other gene contains at least 14 intervening sequences. The mRNA gene sequences appear to be similar; at least 60% divergence was found between the intervening sequences of the two delta-crystallin genes. Insertions or deletions or both appear to be major events responsible for these differences.
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PMID:Comparison of two delta-crystallin genes in the chicken. 625 68

Double-stranded DNA was synthesized from delta-crystallin mRNA prepared from lens fibers of 15-day-old chick embryos and cloned at the Pst I site of the plasmid pBR322. Using the cloned cDNA and single-stranded cDNA as hybridization probes, a number of genomic DNA fragments containing delta-crystallin gene sequences have been cloned from the partial and complete EcoRI digests of chick brain DNA. One of the clones from the partial digests contains a DNA fragment that consists of four EcoRI fragments of 7.6 kb, 4.0 kb, 2.6 kb, and 0.8 kb. The gene sequences reside in the (5')7.6 kb - 0.8 kb - 4.0 kb (3') fragments. Electron microscopy has provided evidence that the cloned DNA fragment includes the entire gene sequences complementary to delta-crystallin mRNA except for the 3' terminal poly(A) tail, and that the delta-crystallin gene is interrupted by at least 13 intervening sequences. Another clone contains a genomic fragment that consists of two EcoRI fragments of 3.0 kb and 11 kb. The DNA fragment in the latter clone represents a different delta-crystallin gene, as judged by restriction endonuclease mapping and by electron microscopy.
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PMID:Organization of delta-crystallin genes in the chicken. 628 14

Recently determined X-ray crystal structures of moonlighting proteins are helping to elucidate how a protein can evolve two different functions and, in some cases, switch between its two functions in response to cellular conditions. X-ray crystal structures of the I-AniI homing endonuclease/maturase and the PutA proline dehydrogenase/transcription factor have provided evidence that these proteins utilize separate protein surfaces for their multiple functions. Also, the structure of the DegP (HtrA) protease/chaperone has revealed information about the mechanism of its chaperone activity and suggests how the protein regulates its protease activity. Comparing the structure of eta-crystallin/retinal dehydrogenase with structures of its single-function enzyme homologs provides clues to changes in the protein structure that may have improved its ability to serve as a crystallin, but at the same time may have adversely affected its catalytic activity.
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PMID:Molecular mechanisms for multitasking: recent crystal structures of moonlighting proteins. 1558 89