Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.64 (proteinase K)
 4,071 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have found a novel activity in Tetrahymena cell free extracts that adds tandem TTGGGG repeats onto synthetic telomere primers. The single-stranded DNA oligonucleotides (TTGGGG)4 and TGTGTGGGTGTGTGGGTGTGTGGG, consisting of the Tetrahymena and yeast telomeric sequences respectively, each functioned as primers for elongation, while (CCCCAA)4 and two nontelomeric sequence DNA oligomers did not. Efficient synthesis of the TTGGGG repeats depended only on addition of micromolar concentrations of oligomer primer, dGTP, and dTTP to the extract. The activity was sensitive to heat and proteinase K treatment. The repeat addition was independent of both endogenous Tetrahymena DNA and the endogenous alpha-type DNA polymerase; and a greater elongation activity was present during macronuclear development, when a large number of telomeres are formed and replicated, than during vegetative cell growth. We propose that the novel telomere terminal transferase is involved in the addition of telomeric repeats necessary for the replication of chromosome ends in eukaryotes.
 ...
PMID:Identification of a specific telomere terminal transferase activity in Tetrahymena extracts. 1505 91

Two distinct nuclear antigens, designated NSpI and NSpII, have been characterized and differentiated from the centromeric antigen that reacts with sera from patients with the CREST syndrome. Both NSpI and NSpII produce a speckled pattern of indirect immunofluorescence on HEp-2 cells that resembles the pattern seen with anticentromere antibodies (ACA). They are differentiated from the ACA staining pattern by the absence of metaphase chromatin staining by NSpI antisera and by the absence of a discrete speckled pattern of staining by NSpII. Further, both NSpI and NSpII stain predominantly the peritubular nuclei of mouse kidney cryostat sections. NSpII is sensitive to trypsin, proteinase K, and HCI extraction, suggesting that it is a relatively soluble nuclear protein. NSpI was also sensitive to protease treatment but was not extracted with 0.1N HCl, suggesting that it is a tightly bound nuclear protein.
 ...
PMID:Speckled pattern antinuclear antibodies resembling anticentromere antibodies. 619 78

Fluorescence in situ hybridization (FISH) and specific DNA probes for peri-centromeric repeat regions and unique sequence loci have made it possible to study chromosomal aberrations from interphase tumor nuclei. Large-scale retrospective studies on the prognostic value of interphase cytogenetics would become feasible if these techniques were readily applicable to nuclei from archival formalin-fixed tumor tissues. We describe here an improved technique for interphase FISH analysis of tumors that have been extensively fixed in formalin. The protocol aims at improving probe penetration and hybridization efficiency by inducing chromatin decondensation and swelling of the nuclei with a heat treatment in a 90 degrees C glycerol solution prior to hybridization. Using this cell pretreatment, FISH results on the detection of chromosome copy number aberrations and amplification of the c-erbB-2 oncogene from formalin-fixed, paraffin-embedded tissues were highly concordant with those from fresh tissues. In contrast to previously described methods, separate adjustments of denaturation or proteinase K digestion are not required for each sample. This method facilitates retrospective analyses of large series of tumors and is also useful for applying FISH to routine diagnostic purposes using formalin-fixed material.
 ...
PMID:Improved technique for analysis of formalin-fixed, paraffin-embedded tumors by fluorescence in situ hybridization. 792 86

Multidrug-resistant KB-V1 cells carry amplified mdrl gene sequences located in an extrachromosomal compartment (on episomes). Since episomes do not contain centromeric or telomeric sequences it is unclear whether they are able to bind to nuclear matrix proteins that may regulate episomal gene expression. Using high salt treatments followed by in situ hybridization and dot blot analyses we found evidence for direct binding of episomal DNA to nuclear matrix proteins. This binding could only be reversed after incubation with trypsin or proteinase K as determined by contour-clamped homogeneous electric field (CHEF) electrophoresis. Our findings are consistent with the concept that circular extrachromosomal DNA may not only reintegrate into nuclear DNA but may also be subject to functional control by regulatory proteins within the nuclear matrix.
 ...
PMID:Evidence for binding of extrachromosomal DNA sequences to nuclear matrix proteins in multidrug-resistant KB-V1 cells. 845 45

Fluorescence in situ hybridization (FISH) is a reliable method for tagging centromeric regions of specific chromosomes in interphase nuclei. Not only is FISH useful for chromosome enumeration, but as region-specific chromosome probes are developed, the clinical applications and potentials for use by pathologists are extensive. This technique lends itself particularly to use in cytology preparations because the cells are disaggregated and monolayer preparations yield excellent technical hybridization results. Over a 7-mo period we processed cytologic samples in an attempt to define and outline a method for optimal specimen processing for FISH use in cell suspensions, techniques applicable to all fresh cytology specimens which can also be used for the processing of surgical pathology aspirates and other material. All samples should be promptly processed to ensure specimen viability, and triaged on an individual basis to ensure preparation of moderately cellular monolayered cytospins. Equivalent nuclear probe signals have been obtained with several sample fixation methods: air-drying, 95% ethanol, methanol (Diff-Quik fixative), and Carnoy's solution. No difference was noted in the nuclear probe signals or specimen adhesion on positively charged or noncharged slides. After initial fixation our slides remained at room temperature until FISH was performed, without any adverse effects. A short digestion with proteinase K and subsequent rehybridization yielded positive results on samples that originally yielded poor nuclear probe signals.
 ...
PMID:Fluorescence in situ hybridization (FISH): a user's guide to optimal preparation of cytologic specimens. 883 24

The nuclear PET309 gene of Saccharomyces cerevisiae is necessary for expression of the mitochondrial COX1 gene, which encodes subunit I of cytochrome c oxidase. In a pet309 null mutant, there is a defect both in accumulation of COX1 pre-RNA, if it contains introns, and in translation of COX1 RNAs [Manthey, G. M. & McEwen, J. E. (1995) EMBO J. 14, 4031-4043]. To facilitate identification and intracellular localization of the protein Pet309p, that is encoded by the PET309 gene, Pet309p was tagged at the carboxy terminus with an epitope from the human c-myc protein. A monoclonal antibody against the c-myc epitope detected a 98-kDa protein in mitochondria of yeast cells that expressed the PET309-c-myc fusion protein from a high copy number plasmid. This protein was not detectable in cells that did not express the fusion protein, or that expressed it from a single copy centromeric vector. Additional analyses of mitochondrial subfractions demonstrated that the PET309-c-myc fusion protein is localized specifically in the inner mitochondrial membrane. It could not be extracted by alkaline sodium carbonate, yet it was susceptible to proteinase K digestion in mitoplasts (mitochondria with a disrupted outer membrane). These results indicate that Pet309p spans the inner membrane, with domain(s) exposed to the intermembrane space side of the membrane. How Pet309p may function in concert with other gene products necessary for COX1 RNA translation or accumulation, such as Mss51p or Nam1p, respectively, is discussed.
 ...
PMID:The Saccharomyces cerevisiae Pet309 protein is embedded in the mitochondrial inner membrane. 969 14

Telomerase is a ribonucleoprotein enzyme that can elongate telomeric DNA, which is thought to be required for the development of cellular immortality and oncogenesis in mammals. We examined telomerase activity in tissues and primary cultured lymphoid cells of adult penaeid shrimps. Using the telomeric repeat amplification protocol (TRAP), we studied the characteristics of a putative novel telomerase in Penaeus japonicus. This telomerase could be inactivated by heating or treatment with RNase A or proteinase K. At elongation, this telomerase required dATP, dGTP, and dTTP, but not dCTP, as substrates. Sequence analysis of the TRAP product revealed that this telomerase synthesized (TTAGG)(n) repeated sequences. The activity of this telomerase was decreased but still readily detectable in 100 ng of protein extract from lymphoid tissue. The telomerase activity was detected in all examined tissues including testis, ovary, lymphoid, heart, hepatopancreas, and muscle. The highest telomerase activity was in the extract of ovarian tissues. In primary cultured lymphoid cells, the telomerase activity was retained. Thus, primary cultured lymphoid cells of Penaeus japonicus possess one of the factors necessary for cell line establishment.
 ...
PMID:Detection of telomerase activity in tissues and primary cultured lymphoid cells of Penaeus japonicus. 1513 20

Scanning electron microscopy (SEM) proves to be an appropriate technique for imaging chromatin organization in meiosis I and II of rye (Secale cereale) down to a resolution of a few nanometers. It could be shown for the first time that organization of basic structural elements (coiled and parallel fibers, chromomeres) changes dramatically during the progression to metaphase I and II. Controlled loosening with proteinase K (after fixation with glutaraldehyde) provides an enhanced insight into chromosome architecture even of highly condensed stages of meiosis. By selective staining with platinum blue, DNA content and distribution can be visualized within compact chromosomes as well as in a complex arrangement of fibers. Chromatin interconnecting threads, which are typically observed in prophase I between homologous and non-homologous chromosomes, stain clearly for DNA. In zygotene transversion of chromatid strands to their homologous counterparts becomes evident. In pachytene segments of synapsed and non-synapsed homologs alternate. At synapsed regions pairing is so intimate that homologous chromosomes form one filament of structural entity. Chiasmata are characterized by chromatid strands which traverse from one homolog to its counterpart. Bivalents are characteristically fused at their telomeric regions. In metaphase I and II there is no structural evidence for primary and secondary constrictions.
 ...
PMID:Ultrastructural analysis of chromatin in meiosis I + II of rye (Secale cereale L.). 1521 70

The chromosomal ends of Leishmania (Leishmania) amazonensis contain conserved 5'-TTAGGG-3' telomeric repeats. Protein complexes that associate in vitro with these DNA sequences, Leishmania amazonensis G-strand telomeric protein (LaGT1-3), were identified and characterized by electrophoretic mobility shift assays and UV cross-linking using protein fractions purified from S100 and nuclear extracts. The three complexes did not form (a) with double-stranded DNA and the C-rich telomeric strand, (b) in competition assays using specific telomeric DNA oligonucleotides, or (c) after pretreatment with proteinase K. LaGT1 was the most specific and did not bind a Tetrahymena telomeric sequence. All three LaGTs associated with an RNA sequence cognate to the telomeric G-rich strand and a complex similar to LaGT1 is formed with a double-stranded DNA bearing a 3' G-overhang tail. The protein components of LaGT2 and LaGT3 were purified by affinity chromatography and identified, after renaturation, as approximately 35 and approximately 52 kDa bands, respectively. The <or= 15 kDa protein component of LaGT1 was gel-purified as a UV cross-linked complex of approximately 18-20 kDa. Peptides generated from trypsin digestion of the affinity and gel-purified protein bands were analysed by matrix-assisted laser desorption/ionization-time of flight and electrospray ionization tandem mass spectrometry. The fingerprint and amino acid sequence analysis showed that the protein components of LaGT2 and of LaGT3 were, respectively, similar to the kinetoplastid Rbp38p and to the putative subunit 1 of replication protein A of Leishmania spp., whereas the <or= 15 kDa protein component of LaGT1 was probably a novel Leishmania protein.
 ...
PMID:Identification of three proteins that associate in vitro with the Leishmania (Leishmania) amazonensis G-rich telomeric strand. 1523 2

Fluorescent in situ hybridization (FISH) represents a moden molecular pathology technique, alternative to conventional cytogenetics (karyotyping). In addition to metaphase spreads, it can be applied directly to interphase nuclei. The latter makes the FISH technique powerful for pathologists for it integrates molecular genetics and classic cytogenetics and brings them together to a single framework for morphologic evaluation. Interphase FISH can be applied to imprints from fresh tissue or to paraffin sections after proteinase K digestion. Centromeric, telomeric and locus DNA-sequence specific probes can be used to identify aneuploidy or gene mutations. Several protocols combine molecular cytogenetics with classic karyotyping. Other sophisticated, FISH-based protocols have been introduced. Among them, comparative genomic hybridization is very important for it can detect non-balanced chromosomal aberrations of uncultured tumor cells and provide overall genomic information in a single experiment. This review presents the principles and applications of FISH technique for the investigation of the cytogenetic background of pituitary adenomas.
 ...
PMID:Molecular cytogenetics of pituitary adenomas, assessed by FISH technique. 1528 48


1