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Query: UNIPROT:P50583 (asymmetrical)
 12,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ten samples of lymphocytes coming from patients affected by chronic lymphatic leukemia and ten samples from normal subjects were studied by FT-IR spectroscopy. Spectral differences observed between the two kinds of cells correspond to an increase of the intensities, in the leukemic samples with respect to the normal ones, of the bands corresponding mainly to PO2- symmetrical and asymmetrical stretching vibrations of DNA. The ratios of the integrated areas of the band at 1080 cm-1 mainly involving the symmetrical stretching vibration of the O-P-O linkages of DNA, and of the band at 1540 cm-1, due to the proteic components of the lymphocytes, assume different values for the two kinds of cells. These ratios can constitute an additional marker to diagnose chronic lymphatic leukemia and may be usefully employed to evidence the early phases of the disease.
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PMID:New possibilities of research in chronic lymphatic leukemia by means of Fourier transform-infrared spectroscopy--II. 404 31

When short pulses of [(3)H]uracil were administered to Bacillus subtilis infected with phage 2C, the main species of labeled RNA was a 10S component that hybridized chiefly, but not exclusively, with the heavy strand of 2C DNA. After long pulses, most of the radioactivity was found in the 23S, 16S, and 5S rRNA's, which are coded for by the cell genome. Formation of such RNA species was reduced but not suppressed upon infection, the extent of inhibition being proportional to the virus-to-cell ratio. When bacteria were incubated with virginiamycin, an inhibitor of protein synthesis, and then infected with phage 2C, formation of virus-specific RNA decreased. This antibiotic also reduced the preferential transcription of the heavy strand of 2C DNA. The methylation pattern of rRNA remained unchanged upon infection with phage 2C. Virginiamycin reduced both the methylation and stability of rRNA in uninfected cells; this effect, however, was clearly reduced during the viral cycle. It can be concluded that in 2C-infected B. subtilis, cellular and viral RNA species are simultaneously synthesized and a preferential transcription of viral message depends not only on the number of available copies of viral template, but also on their translation. Moreover, virus-dictated proteins are responsible for the inhibition of cellular RNA formation as well as for the asymmetrical transcription of phage genome. Finally, virginiamycin and phage 2C have antagonistic, nonoverlapping effects on the metabolism and function of the RNA of the host cell.
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PMID:Origin and metabolic properties of the RNA species formed during the replication cycle of virus 2C. 421 50

Genetic analyses of 48-hr-old zygote-daughter-colony cells from crosses between chloramphenicol and erythromycin resistance markers located in mitochondrial DNA demonstrated homoplasmons of parental and recombinant genotypes, and heteroplasmons with recombinant and/or parental genotypes. Although the heteroplasmons were unstable and the homoplasmic components could be segregated by plating on selective media, the heteroplasmic state was often maintained beyond 19 cell divisions when grown on non-selective medium. Homoplasmons of recombinant genotype from repulsion crosses were observed with a frequency of 7.2, 9.0, 11.2 and 11.4 percent; two crosses with the resistance markers in coupling had 5.4 and 11.5 percent recombinants. Under non-selective conditions, the mitochondrial marker derived from the haploid parent of a mating type predominated in zygote-daughter-cells; this asymmetrical distribution could be reversed by selective pressure for the marker transmitted with low frequency. The challenge with chloramphenicol and erythromycin of zygotes from crosses of resistance-markers in repulsion revealed that inter-mitochondrial complementation was not occurring.
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PMID:Somatic segretation, recombination, asymmetrical distribution and complementation tests of cytoplasmically-inherited antibiotic-resistance mitochondrial markers in S. cerevisiae. 456 99

The positions of three single-strand interruptions in the DNA of phage T5(+) have been located by electron microscopy. All three interruptions were found in the same strand. Uneven base composition along the molecule is indicated by the preferential melting of certain regions. The data suggest a model according to which (1) the first-step-transfer DNA section is separated by a single-strand interruption from the rest of the phage genome, (2) the phage carries only one such section and therefore transfers the asymmetrical DNA molecule always in the same direction into the host cell, and (3) single-strand interruptions are points of preferred breakage.
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PMID:Location of single-strand interruptions in the DNA of bacteriophage T5. 525 14

In maturing oocytes of the newt Triturus viridescens, the nucleoli undergo a series of morphological changes that are very similar to those described by Callan for the axolotl, Ambystoma mexicanum. The nucleoli first assume the form of spheroids which then become extended into ring or necklace shapes that are DNase-sensitive; in mature oocytes the nucleoli revert to a spheroidal form. Short term in vitro incorporation studies with uridine-(3)H on both species show that RNA synthesis occurs in a restricted, eccentric portion of the spheroidal nucleoli, thereby producing an asymmetrical pattern of labeling. In the ring forms, however, the localization of the radioactivity suggests that synthesis takes place symmetrically throughout their entire length. The changes in nucleolar morphology apparently reflect the fact that the component DNA has undergone a redistribution from a localized region in the spheroidal nucleoli to an extended circle in the rings; the patterns of uridine-(3)H incorporation, therefore, parallel the distribution of DNA in both the spheroidal and the ring nucleoli. Ultrastructurally, the nucleoli contain a fibrillar component that corresponds in position to that of the DNA. The typical spheroidal nucleolus consists of a fibrillar core situated eccentrically and surrounded by a hull of granular, ribonucleoprotein material. The ring nucleoli are composed of a central fibrous region that is ensheathed all around its circumference by a layer of similar granular material. This granular substance is thicker at intervals along the length of the rings, representing the "beads" of the necklaces.
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PMID:Spheroidal and ring nucleoli in amphibian oocytes. Patterns of uridine incorporation and fine structural features. 605 93

We have developed a selection procedure for mutants obtained by oligonucleotide directed mutagenesis based on asymmetrical A-methylation of GATC-sequences in the duplex DNA. The method involves the construction of gapped duplexes of circular single-stranded phage DNA. An oligonucleotide, complementary to part of the gap except for a single mismatch, is hybridized to the gapped duplex DNA and the remaining single stranded regions are filled-in enzymatically. When the template is undermethylated, the yield of mutants is almost solely dependent on the priming efficiency of the oligonucleotide. The approach was used to introduce an AT----CG transversion in the mut L region of phage lambda. Under optimal conditions, about 50-60% of the transformants were of the mutant genotype. Although situated adjacent to a known nut L mutation, the present mutation was phenotypically silent. The possibility of screening for mutants by means of a coupled, easily detectable marker was also investigated.
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PMID:Oligonucleotide directed mutagenesis: selection of mutants by hemimethylation of GATC-sequences. 609 41

Purkinje's cells from the rat cerebellum were exposed to UV cytophotometry in order to evaluate the nucleic acid content in the nucleoli and perinucleolar chromatin. The study revealed an asymmetrical histogram of RNA distribution in the Purkinje's cell nucleoli. The cells with an increased RNA content in the nucleolus displayed the elevated quantities of nucleic acids in the perinuclear chromatin. A relationship of the phenomenon under study and the hypothesis of ribosomal DNA amplification in Purkinje's cells is discussed.
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PMID:[Asymmetric histogram of nucleolar nucleic acid concentration as a potential index of ribosomal DNA amplification in rabbit cerebellar Purkinje cells]. 615 14

Labelled RNA preparations (total newly synthesized RNA, as well as stable cytoplasmic RNA) isolated from a cell culture of D. melanogaster were hybridized in situ with polytene chromosomes. Apart from the nucleolus, in all cases the regions adjacent to the chromocentre in the polytene chromosomes and the intercalary heterochromatin regions in the X chromosome and the autosomes are the most intensively labelled. In the case of asynapsis of polytene chromosomes in heterozygotes the label is detected in a number of intercalary heterochromatin sites in one homologue only ("the asymmetrical label"). The same kind of radioactivity distribution in intercalary heterochromatin regions was observed after a hybridization of polytene chromosomes with cloned DNA fragments (Ananiev et al., 1978, 1979) coding for the abundant classes of messenger RNA (Ilyin et al., 1978) in a cultured D. melanogaster cells. In some regions of intercalary heterochromatin which do not contain these fragments the "'asymmetrical" type of label distribution is observed after hybridization with cell RNA. - These results lead one to regard the intercalary heterochromatin regions as "nests" comprising different types of actively transcribable genes, the composition of each nest varying in different stocks of D. melanogaster.
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PMID:Transcription of intercalary heterochromatin regions in Drosophila melanogaster cell culture. 615 41

Chloroplast DNA from Euglena gracilis was used to construct a partial library of recombinant plasmids representing 45% of the DNA. Each plasmid was radioactively labeled in vitro by nick translation and hybridized in liquid to a vast excess of total cellular RNA isolated either from cells grown continually in the dark or from cells containing developing chloroplasts. The complexity and abundance of the RNA that hybridized to the different chloroplast restriction endonuclease DNA fragments were calculated from the RNA-DNA hybridization saturation values and the pseudo-first-order hybridization rate constants, respectively. The complexity of these transcripts showed little change during chloroplast development. In several cases, the complexity of the RNA was greater than expected for asymmetrical transcription, suggesting the possibility that transcription may be symmetrical in some regions of chloroplast DNA. The abundance of the transcripts ranged from 0.0001% to nearly 10% of the total cellular RNA, and in some cases changed by as much as 5-10-fold during chloroplast development.
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PMID:Complexity and abundance of ribonucleic acid transcribed from restriction endonuclease fragments of Euglena chloroplast deoxyribonucleic acid during chloroplast development. 616 84

bI1 RNA (excised from the first intron of the long form of the cytochrome b gene of Saccharomyces cerevisiae mitochondria) hybridizes with the two strands of a Bg/II-MboI DNA segment from this region. This fraction is resistant to digestions by DNase I and RNase T1 and disappears completely upon alkali hydrolysis. Strand-specific labeling of an intronic DNA fragment, cloned in pBR322 plasmid, was accomplished through the use of a T4 DNA polymerase. The purity of the probes was demonstrated by cloning an exon-intron fragment and labeling it by the same procedure; mRNA and pre-mRNA bands hybridized only with the transcribed DNA strand whereas bI1 RNA hybridized with the two strands under the stringent washing conditions employed (tm + 20 degrees C). Several experimental results argue against the possibility that the observation of two complementary bI1 RNA strands results from a partial self-complementarity of the RNA. A pre-mRNA intermediate from a box8 (G5046) mutant, still containing this intron, hybridizes only with the transcribed DNA strand of the pure intronic probe. The amount of the non-sense bI1 RNA strand is very low, in cells from two wild-type strains, relative to the sense RNA strand during the early stages of growth on glucose. It increases as the cells are released from glucose repression. bI1 RNA is resistant to RNase. Very little self-complementarity is seen by computer analysis of the sequence. Purified bI1 RNA is seen by electron microscopy under non-denaturing conditions as a mixture of double-stranded circular and linear molecules thus confirming the existence of the two complementary strands. The disappearance of all material following alkali hydrolysis demonstrates that these are indeed two RNA strands. Under fully denaturing conditions a mixture of single-stranded circular and linear molecules is seen as reported previously (Cell, 19, 321-329, 1980). We conclude that yeast mitochondria contain the two complementary bI1 RNA strands, one circular and the other linear. Considering a largely asymmetrical transcription of the mitochondrial genome in yeast and assuming that circularization of some intronic RNAs is part of RNA processing, we do not believe that the two strands are each a mixture of linear and circular molecules. The ratio of non-sense to sense bI1 RNA in a cytoplasmic petite mutant, A1B1, also varies according to growth conditions.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Yeast mitochondria contain a linear RNA strand complementary to the circular intronic bI1 RNA of cytochrome b. 620 24


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