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Specht CA, Novotny CP, Ullrich RC. Strain specific differences in ribosomal DNA from the fungus Schizophyllum commune. Curr Genet 2013; 8:219-22. [PMID: 24177742 DOI: 10.1007/bf00417819] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/1983] [Indexed: 11/29/2022]
Abstract
CsCl-bisbenzimide gradients were used to purify ribosomal DNA (rDNA) from Schizophyllum commune total DNA. Southern hybridizations demonstrate that this DNA codes for rRNA. Restriction mapping of the rDNA from four strains revealed strain variation with repeat lengths of 9.2-9.6 kbp. Specific differences in the length of the rDNA repeat in different strains are due to insertions of 0.2 or 0.4 kbp of DNA at a single site. Different strains also show restriction site polymorphisms. Our analysis demonstrates the caution that must be exercised when interpreting restriction data from genomes containing restriction polymorphisms. Restriction digests with MspI and HpaII indicate that the rDNA contains 5-methylcytosine and that the unit repeats are not methylated identically, but rather differentially. This is the first report of methylated rDNA in fungi.
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Affiliation(s)
- C A Specht
- Department of Botany, University of Vermont, 05405, Vermont, Burlington, USA
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2
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Yeast L double-stranded ribonucleic acid is synthesized during the G1 phase but not the S phase of the cell cycle. Mol Cell Biol 1997. [PMID: 9279380 DOI: 10.1128/mcb.1.8.673] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The cytoplasm of Saccharomyces cerevisiae contains two major classes of protein-encapsulated double-stranded ribonucleic acids (dsRNA's), L and M. Replication of L and M dsRNA's was examined in cells arrested in the G1 phase by either alpha-factor, a yeast mating pheromone, or the restrictive temperature for a cell cycle mutant (cdc7). [3H]uracil was added during the arrest periods to cells prelabeled with [14C]uracil, and replication was monitored by determining the ratio of 3H/14C for purified dsRNA's. Like mitochondrial deoxyribonucleic acid, both L and M dsRNA's were synthesized in the G1 arrested cells. The replication of L dsRNA was also examined during the S phase, using cells synchronized in two different ways. Cells containing the cdc7 mutation, treated sequentially with alpha-factor and then the restrictive temperature, enter a synchronous S phase when transferred to permissive temperature. When cells entered the S phase, synthesis of L dsRNA ceased, and little or no synthesis was detected throughout the S phase. Synthesis of L dsRNA was also observed in G1 phase cells isolated from asynchronous cultures by velocity centrifugation. Again, synthesis ceased when cells entered the S phase. These results indicate that L dsRNA replication is under cell cycle control. The control differs from that of mitochondrial deoxyribonucleic acid, which replicates in all phases of the cell cycle, and from that of 2-micron DNA, a multiple-copy plasmid whose replication is confined to the S phase.
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3
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Taylor SS, Larin Z, Tyler-Smith C. Analysis of extrachromosomal structures containing human centromeric alphoid satellite DNA sequences in mouse cells. Chromosoma 1996; 105:70-81. [PMID: 8753696 DOI: 10.1007/bf02509516] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Yeast artificial chromosomes (YACs) spanning the centromeric region of the human Y chromosome were introduced into mouse LA-9 cells by spheroplast fusion in order to determine whether they would form mammalian artificial chromosomes. In about 50% of the cell lines generated, the YAC DNA was associated with circular extrachromosomal structures. These episomes were only present in a proportion of the cells, usually at high copy number, and were lost rapidly in the absence of selection. These observations suggest that, despite the presence of centromeric sequences, the structures were not segregating efficiently and thus were not forming artificial chromosomes. However, extrachromosomal structures containing alphoid DNA appeared cytogenetically smaller than those lacking it, as long as yeast DNA was also absent. This suggests that alphoid DNA can generate the condensed chromatin structure at the centromere.
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Affiliation(s)
- S S Taylor
- CRC Chromosome Molecular Biology Group, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
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4
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Pasero P, Marilley M. Size variation of rDNA clusters in the yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe. MOLECULAR & GENERAL GENETICS : MGG 1993; 236:448-52. [PMID: 8437591 DOI: 10.1007/bf00277147] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The higher-order organization of rRNA genes was investigated in the yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe. We used pulsed-field gel electrophoresis (PFGE) in combination with frequent cutter endonucleases having no recognition sites within rDNA repeating units to characterize tandem arrays of ribosomal genes in these two species. Large variations in rDNA cluster length were detected in various S. cerevisiae and S. pombe strains commonly used as PFGE molecular weight markers. This wide range of variability implies that the sizes currently assessed for chromosomes bearing rRNA genes in these organisms are unreliable since they may vary within strains by several hundreds of kilobase pairs, depending on the size of the tandem arrays of rRNA genes. Consequently, there is now a lack of reliable PFGE size standards between 1.6 Mb and 4.5 Mb, even when established yeast strains with calibrated chromosomes are used.
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Affiliation(s)
- P Pasero
- Laboratoire de Génétique, URA CNRS 1189, Faculté de Médecine, Marseille, France
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5
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Kerrebrock AW, Srivastava R, Gerbi SA. Isolation and characterization of ribosomal DNA variants from Sciara coprophila. J Mol Biol 1989; 210:1-13. [PMID: 2555520 DOI: 10.1016/0022-2836(89)90286-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The ribosomal RNA multigene family in the fungus fly Sciara coprophila contains a total of only 65 to 70 repeat units. We explored the types and frequencies of variant repeats in this small multigene family by characterizing different cloned rDNA variants from Sciara. Although we did not observe any intergenic spacer length variants in Sciara, we found a variant due to the insertion of a putative mobile element (lambda Bc11), and variants containing ribosomal insertion elements. By DNA sequence analysis of rDNA/non-rDNA junctions, there are three distinct types of ribosomal insertion elements found in Sciara rDNA: two correspond to the R1 and R2 insertion elements found in other dipterans (clones lambda Bc5 and pBc1L1, respectively), and one is a novel class of ribosomal insertion elements (R3, exemplified by clone pBc6D6) which so far is unique to Sciara. Together, the several different rDNA variants make up from 12 to 20% of the rDNA in Sciara. These results are discussed in the context of evolution of the ribosomal RNA multigene family.
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Affiliation(s)
- A W Kerrebrock
- Division of Biology and Medicine, Brown University, Providence, RI 02912
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6
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Restrepo BI, Barbour AG. Cloning of 18S and 25S rDNAs from the pathogenic fungus Cryptococcus neoformans. J Bacteriol 1989; 171:5596-600. [PMID: 2676980 PMCID: PMC210402 DOI: 10.1128/jb.171.10.5596-5600.1989] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Cryptococcus neoformans is an important pathogenic fungus that has been classified as a basidiomycete. Little is known of the molecular genetics of this fungal pathogen. To begin such studies, we devised a procedure for extraction of DNA from cryptococci; this method involved the use of the cell wall-active enzyme NovoZym 234. Using cloned rDNA of Saccharomyces cerevisiae as a probe, we identified homologous restriction fragments in a Southern blot of digested C. neoformans DNA. An 8.6-kilobase HindIII fragment that hybridized with the yeast rDNA probe was ligated with the vector pBR322 and cloned into Escherichia coli. When the fragment was used as a probe, it hybridized to the 18S and 25S rRNAs of C. neoformans in Northern (RNA) blots of native and denatured RNA. It bound at high stringency only weakly to the rRNAs of the ascomycete S. cerevisiae. The locations of the genes for 5/5.8S, 18S, and 25S subunits in the cloned fragment were identified with labeled rRNA of these different types.
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Affiliation(s)
- B I Restrepo
- Department of Medicine, University of Texas Health Science Center, San Antonio 78284
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7
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Anand R, Villasante A, Tyler-Smith C. Construction of yeast artificial chromosome libraries with large inserts using fractionation by pulsed-field gel electrophoresis. Nucleic Acids Res 1989; 17:3425-33. [PMID: 2542900 PMCID: PMC317785 DOI: 10.1093/nar/17.9.3425] [Citation(s) in RCA: 137] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
A method for constructing yeast artificial chromosome (YAC) libraries with large insert sizes is reported. High molecular weight human DNA was partially digested with EcoRI and cloned in the vector pYAC4. When unfractionated DNA was used, the mean YAC size was 120kb. Fractionation by pulsed-field gel electrophoresis using a 'waltzer' apparatus to remove small DNA fragments increased the mean YAC size to congruent to 220kb or congruent to 370kb depending on the fractionation conditions. Ligated DNA prepared by this method was stable at 4 degrees C and routinely yielded transformation efficiencies of greater than 700 colonies/micrograms. It should be possible to extend the method to produce even larger inserts and to use high molecular weight DNA from any source.
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Affiliation(s)
- R Anand
- Department of Biochemistry, University of Oxford, UK
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8
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Arnold J, Cuticchia AJ, Newsome DA, Jennings WW, Ivarie R. Mono- through hexanucleotide composition of the sense strand of yeast DNA: a Markov chain analysis. Nucleic Acids Res 1988; 16:7145-58. [PMID: 3043378 PMCID: PMC338357 DOI: 10.1093/nar/16.14.7145] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Here we compare several methods for predicting oligonucleotide frequencies in 392 kb of yeast DNA. As in previous work on E. coli, a relatively simple equation based on tetranucleotide frequencies can be used in predicting the frequencies of longer oligonucleotides. For example, the mean of observed/expected abundances of 4,096 hexamers was 1.00 with a sample standard deviation of .18. This simple predictor arises by considering each base on the sense strand of yeast to depend only on the three bases 5' to it (a 3rd order Markov chain) and is more accurate in estimating oligonucleotide frequencies than other statistical methods examined. This equation is useful in predicting restriction enzyme fragment sizes, selecting restriction enzymes that cut preferentially in coding vs noncoding regions, and in constructing detailed physical maps of whole genomes. When ranked highest to lowest abundance, the observed frequencies of oligomers of a given length (up to 6 bases) are closely tracked by the predicted abundances of a 3rd or 4th order Markov chain. These ordered abundance curves have a power curve shape with a broad linear range with a sharp break at the top end of the curve. There is also a strong disparity between the most and least abundant oligomer with for example a 79-fold variation between the most and least abundant hexamer. The curves reveal a strong dependence of oligomer frequencies on base composition. Unlike E. Coli, there is no sharp downturn at the low end of the curves and hence, no class of oligomers rare relative to other oligomers of the same length.
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Affiliation(s)
- J Arnold
- Department of Genetics, University of Georgia, Athens 30602
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9
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Weber H, Barth G. Nonconventional yeasts: their genetics and biotechnological applications. Crit Rev Biotechnol 1988; 7:281-337. [PMID: 3064923 DOI: 10.3109/07388558809150535] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
To date, more than 500 species of yeasts have been described. Most of the genetic and biochemical studies have, however, been carried out with Saccharomyces cerevisiae. Although a considerable amount of knowledge has been accumulated on fundamental processes and biotechnological applications of this industrially important yeast, the large variety of other yeast genera and species may offer various advantages for experimental study as well as for product formation in biotechnology. The genetic investigation of these so-called unconventional yeasts is poorly developed and information about corresponding data is dispersed. It is the aim of this review to summarize and discuss the main results of genetic studies and biotechnological applications of unconventional yeasts and to serve as a guide for scientists who wish to enter this field or are interested in only some aspects of these yeasts.
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Affiliation(s)
- H Weber
- Central Institute of Microbiology and Experimental Therapy, Academy of Science GDR, Jena
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10
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Carr LG, Skatrud PL, Ingolia TD, Queener SW. Organization of the 5.8S, 16?18S, and 23?28S ribosomal RNA genes of Cephalosporium acremonium. Curr Genet 1987. [DOI: 10.1007/bf00436881] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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11
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Burke DT, Carle GF, Olson MV. Cloning of large segments of exogenous DNA into yeast by means of artificial chromosome vectors. Science 1987; 236:806-12. [PMID: 3033825 DOI: 10.1126/science.3033825] [Citation(s) in RCA: 959] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Fragments of exogenous DNA that range in size up to several hundred kilobase pairs have been cloned into yeast by ligating them to vector sequences that allow their propagation as linear artificial chromosomes. Individual clones of yeast and human DNA that have been analyzed by pulsed-field gel electrophoresis appear to represent faithful replicas of the source DNA. The efficiency with which clones can be generated is high enough to allow the construction of comprehensive libraries from the genomes of higher organisms. By offering a tenfold increase in the size of the DNA molecules that can be cloned into a microbial host, this system addresses a major gap in existing experimental methods for analyzing complex DNA sources.
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12
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Abstract
An electron microscopic study was made of the replication of rDNA chromatin of Saccharomyces cerevisiae. Two different methods were used to synchronize cells. cdc7-1 cells were raised to a restrictive temperature, whereas A364a cells were blocked with mating factor. Replication bubbles typically opened in the nontranscribed spacers of rDNA repeats in both cell types. The mean position of the center of these bubbles corresponds closely to a position where an autonomously replicating sequence previously has been mapped in an rDNA repeat. Clusters of replication bubbles containing up to four bubbles spaced one to three genes apart were seen opening in early S phase.
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13
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Simmen FA, Mandel M, Humphreys T. Length and sequence polymorphisms in the ribosomal gene spacer of the Hawaiian sea urchin, T. gratilla. Biochem Biophys Res Commun 1986; 137:834-40. [PMID: 3729940 DOI: 10.1016/0006-291x(86)91155-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Blot-hybridization of sea urchin (Tripneustes gratilla) genomic DNA with a cloned rDNA probe revealed individual variation in the length of the rDNA repeat unit and also in the non-transcribed spacer sequences. The number of distinct rDNA repeat subclasses distinguishable within any one sea urchin was limited and usually 2 to 3. However, examination of a number of sea urchins indicated a large number of distinct rDNA repeat types in the population as a whole; all of the rDNA repeat types in nine individuals were different. The presence of limited heterogeneity in the rDNA repeats of single individuals, with may different repeat types in the population as a whole, suggests that rDNA variants can be rapidly and selectively propagated within a chromosomal lineage.
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14
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Saffer LD, Miller OL. Electron microscopic study of Saccharomyces cerevisiae rDNA chromatin replication. Mol Cell Biol 1986; 6:1148-57. [PMID: 3537698 PMCID: PMC367626 DOI: 10.1128/mcb.6.4.1148-1157.1986] [Citation(s) in RCA: 62] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
An electron microscopic study was made of the replication of rDNA chromatin of Saccharomyces cerevisiae. Two different methods were used to synchronize cells. cdc7-1 cells were raised to a restrictive temperature, whereas A364a cells were blocked with mating factor. Replication bubbles typically opened in the nontranscribed spacers of rDNA repeats in both cell types. The mean position of the center of these bubbles corresponds closely to a position where an autonomously replicating sequence previously has been mapped in an rDNA repeat. Clusters of replication bubbles containing up to four bubbles spaced one to three genes apart were seen opening in early S phase.
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15
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Pedersen MB. DNA sequence polymorphisms in the genus saccharomyces III. Restriction endonuclease fragment patterns of chromosomal regions in brewing and other yeast strains. ACTA ACUST UNITED AC 1986. [DOI: 10.1007/bf02907322] [Citation(s) in RCA: 67] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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16
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Fournier P, Gaillardin C, Persuy MA, Klootwijk J, van Heerikhuizen H. Heterogeneity in the ribosomal family of the yeast Yarrowia lipolytica: genomic organization and segregation studies. Gene 1986; 42:273-82. [PMID: 3015740 DOI: 10.1016/0378-1119(86)90231-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The cloned r-DNA units of Yarrowia lipolytica [Van Heerikhuizen et al., 39 (1985) 213-222] and their restriction fragments have been used to probe blots of genomic DNA of this yeast. Wild-type and laboratory strains were shown to contain two-to-five types of repeated units, each strain displaying a specific pattern. By comparing their restriction patterns, we could localize the differences between units within their spacer region. Tetrad analysis strongly suggested a clustered organization of each type of repeat as well as the occurrence of meiotic exchanges within the r-DNA family. Chromosome loss was induced by benomyl and allowed to map several r-DNA clusters on the same chromosome. All those results indicate that the Y. lipolytica r-DNA gene family is quite different from other yeasts.
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17
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Cloning and characterization of the rDNA repeat unit of Podospora anserina. MOLECULAR & GENERAL GENETICS : MGG 1985; 199:154-7. [PMID: 2987647 DOI: 10.1007/bf00327526] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
DNA coding for ribosomal RNA in Podospora anserina has been cloned and was found as a tandemly repeated 8.3 kb sequence. The cloned rDNA was characterized by restriction endonuclease mapping. The location of 5.8S, 18S and 28S rRNA coding regions was established by DNA-RNA hybridization and S1 nuclease mapping. The organization of P. anserina rRNA genes is similar to that of Neurospora crassa and Aspergillus nidulans. The rDNA unit does not contain the sequence coding for 5S RNA.
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18
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Metzenberg RL, Stevens JN, Selker EU, Morzycka-Wroblewska E. Identification and chromosomal distribution of 5S rRNA genes in Neurospora crassa. Proc Natl Acad Sci U S A 1985; 82:2067-71. [PMID: 3157192 PMCID: PMC397493 DOI: 10.1073/pnas.82.7.2067] [Citation(s) in RCA: 113] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The 5S rRNA genes of Neurospora crassa, unlike those of most organisms, are not tandemly arranged, and they are found imbedded in a variety of unique sequences. The 5S rRNA regions of most of the genes are of one type, alpha; however, several other "isotypes" (beta, gamma, delta, zeta, and eta) are also found. We asked whether Neurospora 5S rRNA genes are dispersed on a chromosomal scale and whether genes of different isotypes are spatially segregated. We identified, by DNA sequencing, 5S rRNA genes in 22 5S DNA clones, and we mapped these genes by conventional crosses by using restriction fragment length polymorphisms in their flanking sequences as genetic markers. The results show that the 5S rRNA genes are distributed on at least six of the seven chromosomes. Their location does not appear to be completely random. Some of them are closely linked. One of the chromosomes carries a disproportionate number of 5S rRNA genes of the most common structural type, alpha; another chromosome carries three of the four mapped beta 5S rRNA genes. None of the 5S rRNA genes studied maps close to the nucleolus organizer, the site of the genes that code for the three larger rRNAs.
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19
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Keil RL, Roeder GS. Cis-acting, recombination-stimulating activity in a fragment of the ribosomal DNA of S. cerevisiae. Cell 1984; 39:377-86. [PMID: 6094015 DOI: 10.1016/0092-8674(84)90016-3] [Citation(s) in RCA: 198] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Special mechanisms for stimulating recombination among the nearly identical repeat units of certain multigene families may exist in order to maintain their sequence homogeneity. We have found evidence for such a recombination-stimulating activity in the tandemly repeated ribosomal RNA genes of yeast. A fragment of the yeast ribosomal DNA (rDNA), containing the 5S gene, nontranscribed spacer DNA, and part of the 25S gene, causes a localized stimulation of recombination when inserted at novel locations in the yeast genome. The rDNA fragment stimulates both interchromosomal and intrachromosomal mitotic recombination but not meiotic recombination. To stimulate mitotic recombination, the fragment must act on both copies of the recombining gene. Furthermore, the rDNA fragment stimulates exchange only when inserted with the 5S gene proximal to, and the 25S gene distal to, the recombining alleles.
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20
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Recombination of plasmids into the Saccharomyces cerevisiae chromosome is reduced by small amounts of sequence heterogeneity. Mol Cell Biol 1983. [PMID: 6350848 DOI: 10.1128/mcb.3.7.1204] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
As a model system for studying the properties of mitotic recombination in the yeast Saccharomyces cerevisiae, we have examined recombination between a recombinant plasmid (introduced into the S. cerevisiae cell by transformation) and homologous chromosomal loci. The recombinant plasmids used in these experiments contained S. cerevisiae rRNA genes. We found that the frequency of integrative recombination is sensitive to small amounts of sequence heterogeneity. In addition, the frequency and specificity of these recombination events are affected by the lengths of the interacting homologous DNA sequences.
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21
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Saccharomyces cerevisiae cdc2 mutants fail to replicate approximately one-third of their nuclear genome. Mol Cell Biol 1983. [PMID: 6348512 DOI: 10.1128/mcb.3.6.1000] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Chromosomal DNA replication was examined in temperature-sensitive mutants of Saccharomyces cerevisiae defective in a gene required for the completion of S phase at the nonpermissive temperature, 37 degrees C. Based on incorporation of radioactive precursors and density transfer experiments, strains carrying three different alleles of cdc2 failed to replicate approximately one-third of their nuclear genome at 37 degrees C. Whole-cell autoradiography experiments demonstrated that 93 to 96% of the cells synthesized DNA at 37 degrees C. Therefore, all cells failed to replicate part of their genome. DNA isolated from terminally arrested cells was of normal size as measured on neutral and alkaline sucrose gradients, suggesting that partially replicated DNA molecules do not accumulate and that DNA strands are ligated properly in cdc2 mutants. In addition, electron microscopic examination of the equivalent of more than one genome's DNA from arrested cells failed to reveal any partially replicated molecules. The sequences which failed to replicate at 37 degrees C were not highly specific; eight different cloned sequences replicated to the same extent as total DNA. The 2-microns plasmid DNA and rDNA replicated significantly less well than total DNA, but approximately one-half of these sequences replicated at 37 degrees C. These observations suggest that cdc2 mutants are defective in an aspect of initiation of DNA replication common to all chromosomes such that a random fraction of the chromosomes fail to initiate replication at 37 degrees C, but that once initiated, replication proceeds normally.
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22
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Pedersen MB. DNA sequence polymorphisms in the genus Saccharomyces. I. Comparison of theHIS4 and ribosomal RNA genes in lager strains, ale strains and various species. ACTA ACUST UNITED AC 1983. [DOI: 10.1007/bf02908692] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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23
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Smolik-Utlaut S, Petes TD. Recombination of plasmids into the Saccharomyces cerevisiae chromosome is reduced by small amounts of sequence heterogeneity. Mol Cell Biol 1983; 3:1204-11. [PMID: 6350848 PMCID: PMC370111 DOI: 10.1128/mcb.3.7.1204-1211.1983] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
As a model system for studying the properties of mitotic recombination in the yeast Saccharomyces cerevisiae, we have examined recombination between a recombinant plasmid (introduced into the S. cerevisiae cell by transformation) and homologous chromosomal loci. The recombinant plasmids used in these experiments contained S. cerevisiae rRNA genes. We found that the frequency of integrative recombination is sensitive to small amounts of sequence heterogeneity. In addition, the frequency and specificity of these recombination events are affected by the lengths of the interacting homologous DNA sequences.
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24
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Conrad MN, Newlon CS. Saccharomyces cerevisiae cdc2 mutants fail to replicate approximately one-third of their nuclear genome. Mol Cell Biol 1983; 3:1000-12. [PMID: 6348512 PMCID: PMC368629 DOI: 10.1128/mcb.3.6.1000-1012.1983] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Chromosomal DNA replication was examined in temperature-sensitive mutants of Saccharomyces cerevisiae defective in a gene required for the completion of S phase at the nonpermissive temperature, 37 degrees C. Based on incorporation of radioactive precursors and density transfer experiments, strains carrying three different alleles of cdc2 failed to replicate approximately one-third of their nuclear genome at 37 degrees C. Whole-cell autoradiography experiments demonstrated that 93 to 96% of the cells synthesized DNA at 37 degrees C. Therefore, all cells failed to replicate part of their genome. DNA isolated from terminally arrested cells was of normal size as measured on neutral and alkaline sucrose gradients, suggesting that partially replicated DNA molecules do not accumulate and that DNA strands are ligated properly in cdc2 mutants. In addition, electron microscopic examination of the equivalent of more than one genome's DNA from arrested cells failed to reveal any partially replicated molecules. The sequences which failed to replicate at 37 degrees C were not highly specific; eight different cloned sequences replicated to the same extent as total DNA. The 2-microns plasmid DNA and rDNA replicated significantly less well than total DNA, but approximately one-half of these sequences replicated at 37 degrees C. These observations suggest that cdc2 mutants are defective in an aspect of initiation of DNA replication common to all chromosomes such that a random fraction of the chromosomes fail to initiate replication at 37 degrees C, but that once initiated, replication proceeds normally.
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25
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Purification of yeast RNA polymerases using heparin agarose affinity chromatography. Transcriptional properties of the purified enzymes on defined templates. J Biol Chem 1983. [DOI: 10.1016/s0021-9258(18)32853-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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26
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Gabrielsen OS, Oyen TB. Yeast RNA polymerase I binds preferentially to A+T-rich linkers in rDNA. Nucleic Acids Res 1982; 10:5893-904. [PMID: 6292858 PMCID: PMC320938 DOI: 10.1093/nar/10.19.5893] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Restriction fragments of yeast rDNA retained by purified RNA polymerases on nitrocellulose filters were analysed by gel electrophoresis. The EcoRI fragment B was preferentially retained by RNA polymerase I, but not by RNA polymerase III. The in vivo initiation sites for both polymerases are located within this fragment. Further analysis indicated that the preferred binding site for RNA polymerase I is highly AT-rich regions rather than a true promoter. The reported selective in vitro transcription of rDNA by purified yeast RNA polymerase I could then be explained by this preferential binding.
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Barnitz JT, Cramer JH, Rownd RH, Cooley L, Söll D. Arrangement of the ribosomal RNA genes in Schizosaccharomyces pombe. FEBS Lett 1982; 143:129-32. [PMID: 6288447 DOI: 10.1016/0014-5793(82)80288-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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28
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Borsuk PA, Nagieć MM, Stepień PP, Bartnik E. Organization of the ribosomal RNA gene cluster in Aspergillus nidulans. Gene X 1982; 17:147-52. [PMID: 6282710 DOI: 10.1016/0378-1119(82)90067-1] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
DNA coding for ribosomal RNA in Aspergillus nidulans was found to consist of a unit 7.8 kb in size which is tandemly repeated in the genome and codes for 5.8S, 18S and 26S rRNA. The repeat unit has been cloned, and its restriction map and the location of the individual rRNA coding sequences within the unit have been established.
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29
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Miesfeld R, Krystal M, Arnheim N. A member of a new repeated sequence family which is conserved throughout eucaryotic evolution is found between the human delta and beta globin genes. Nucleic Acids Res 1981; 9:5931-47. [PMID: 6273813 PMCID: PMC327575 DOI: 10.1093/nar/9.22.5931] [Citation(s) in RCA: 204] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
A new class of human interspersed repeated sequences distinct from the AluI family was found by screening a human gene library with a mouse ribosomal gene non-transcribed spacer probe (rDNA NTS). A member of this sequence family was localized to a 251 bp segment between the human delta and beta globin genes: a region previously judged to be devoid of repeated DNA. The complete nucleotide sequence of this segment revealed a tandem block of 17 TG dinucleotides, a feature hypothesized by others to be a recombination hot spot responsible for gene conversion in the gamma globin locus region. When the genomes of Xenopus, pigeon, slime mold and yeast were examined, reiterated sequences homologous to both the mouse rDNA NTS and human globin repeat were found in every case. The discovery of this extraordinarily conserved repeated sequence family appears to have depended upon not using salmon sperm DNA during hybridization. The use of eucaryotic carrier DNA may bias the search for repeated sequences against any which may be highly conserved during eucaryotic evolution.
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Fried H, Pearson N, Kim C, Warner J. The genes for fifteen ribosomal proteins of Saccharomyces cerevisiae. J Biol Chem 1981. [DOI: 10.1016/s0021-9258(19)68759-4] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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31
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Zakian VA, Wagner DW, Fangman WL. Yeast L double-stranded ribonucleic acid is synthesized during the G1 phase but not the S phase of the cell cycle. Mol Cell Biol 1981; 1:673-9. [PMID: 9279380 PMCID: PMC369347 DOI: 10.1128/mcb.1.8.673-679.1981] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The cytoplasm of Saccharomyces cerevisiae contains two major classes of protein-encapsulated double-stranded ribonucleic acids (dsRNA's), L and M. Replication of L and M dsRNA's was examined in cells arrested in the G1 phase by either alpha-factor, a yeast mating pheromone, or the restrictive temperature for a cell cycle mutant (cdc7). [3H]uracil was added during the arrest periods to cells prelabeled with [14C]uracil, and replication was monitored by determining the ratio of 3H/14C for purified dsRNA's. Like mitochondrial deoxyribonucleic acid, both L and M dsRNA's were synthesized in the G1 arrested cells. The replication of L dsRNA was also examined during the S phase, using cells synchronized in two different ways. Cells containing the cdc7 mutation, treated sequentially with alpha-factor and then the restrictive temperature, enter a synchronous S phase when transferred to permissive temperature. When cells entered the S phase, synthesis of L dsRNA ceased, and little or no synthesis was detected throughout the S phase. Synthesis of L dsRNA was also observed in G1 phase cells isolated from asynchronous cultures by velocity centrifugation. Again, synthesis ceased when cells entered the S phase. These results indicate that L dsRNA replication is under cell cycle control. The control differs from that of mitochondrial deoxyribonucleic acid, which replicates in all phases of the cell cycle, and from that of 2-micron DNA, a multiple-copy plasmid whose replication is confined to the S phase.
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Affiliation(s)
- V A Zakian
- Hutchinson Cancer Research Center, Division of Genetics, Seattle, Washington 98104, USA
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32
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Hudspeth ME, Shumard DS, Tatti KM, Grossman LI. Rapid purification of yeast mitochondrial DNA in high yield. BIOCHIMICA ET BIOPHYSICA ACTA 1980; 610:221-8. [PMID: 7011381 DOI: 10.1016/0005-2787(80)90003-9] [Citation(s) in RCA: 99] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
A procedure is presented for the rapid isolation of mitochondrial DNA (mtDNA) in high yield from Saccharomyces cerevisiae. Yeast cells, which may be grown to late stationary phase, are broken by a combination of enzymatic and mechanical means; mtDNA is then isolated from a crude mitochondrial lysate by a single cycle of bisbenzimide-CsCl buoyant density centrifugation. mtDNA so isolated is at least 99.5% pure, and has a mean duplex molecular weight of 24.5 . 10(6). In addition to mtDNA and bulk nuclear DNA, several other yeast nucleic acid species, identified as ribosomal DNA and a mixture of duplex RNAs, form discrete bands in these gradients.
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Brewer BJ, Zakian VA, Fangman WL. Replication and meiotic transmission of yeast ribosomal RNA genes. Proc Natl Acad Sci U S A 1980; 77:6739-43. [PMID: 7005901 PMCID: PMC350364 DOI: 10.1073/pnas.77.11.6739] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The yeast Saccharomyces cerevisiae has approximately 120 genes for the ribosomal RNAs (rDNA) which are organized in tandem within chromosomal DNA. These multiple-copy genes are homogeneous in sequence but can undergo changes in copy number and topology. To determine if these changes reflect unusual features of rDNA metabolism, we have examined both the replication of rDNA in the mitotic cell cycle and the inheritance of rDNA during meiosis. The results indicate that rDNA behaves identically to chromosomal DNA: each rDNA unit is replicated once during the S phase of each cell cycle and each unit is conserved through meiosis. Therefore, the flexibility in copy number and topology of rDNA does not arise from the selective replication of units in each S phase nor by the selective inheritance of units in meiosis.
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Kaback DB, Davidson N. Organization of the ribosomal RNA gene cluster in the yeast Saccharomyces cerevisiae. J Mol Biol 1980; 138:745-54. [PMID: 6997496 DOI: 10.1016/0022-2836(80)90063-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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36
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Clark-Walker GD, Azad AA. Hybridizable sequences between cytoplasmic ribosomal RNAs and 3 micron circular DNAs of Saccharomyces cerevisiae and Torulopsis glabrata. Nucleic Acids Res 1980; 8:1009-22. [PMID: 7003552 PMCID: PMC323969 DOI: 10.1093/nar/8.5.1009] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
We have shown that 2.8 and 3.1 micron circular DNA molecules, previously reported to be present in Saccharomyces cerevisiae and Torulopsis glabrata respectively, contain sequences hybridizing to cytoplasmic ribosomal RNAs. In S. cerevisiae the 2.8 micron circular DNA appears to be identical to the rDNA repeating unit from nuclear DNA, both in length (approximately 9000 base pairs) and in the location of the 25, 18 and 5.8S rRNA sequences on the large HindIII fragment (6500 bp) and the presence of the 5S rRNA sequence on the small HindIII fragment. The 3.1 micron molecule from T. glabrata is approximately 2000 base pairs longer than the S. cerevisiae molecule and in addition, one of the HindIII sites lies within the region hybridizing to 25, 18 and 5.8S rRNAs. In S. cerevisiae the 4-5 copies of the 2.8 micron circular DNA molecules per cell, which have an extra-nuclear location, do not appear to be essential for cell viability as in one strain they were undetectable.
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37
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Marco Y, Rochaix JD. Organization of the nuclear ribosomal DNA of Chlamydomonas reinhardii. MOLECULAR & GENERAL GENETICS : MGG 1980; 177:715-23. [PMID: 6247613 DOI: 10.1007/bf00272684] [Citation(s) in RCA: 39] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Hybridization of cytoplasmic ribosomal RNA (rRNA) to restriction endonuclease digests of nuclear DNA of Chlamydomonas reinhardii reveals two BamHI ribosomal fragments of 2.95 and 2.35 x 10(6) d and two SalI ribosomal fragments of 3.8 and 1.5 x 10(6) d. The ribosomal DNA (rDNA) units 5.3 x 10(6) d in size, appear to be homogeneous since no hybridization of rDNA to other nuclear DNA fragments can be detected. The two BamHI and SalI ribosomal fragments have been cloned and a restriction map of the ribosomal unit has been established. The location of the 25S, 18S and 5.8S rRNA genes has been determined by hybridizing the rRNAs to digests of the ribosomal fragments and by observing RNA/DNA duplexes in the electron microscope. The data also indicate that the rDNA units are arranged in tandem arrays. The 5S rRNA genes are not closely located to the 25S and 18S rRNA genes since they are not contained within the nuclear rDNA unit. In addition no sequence homology is detectable between the nuclear and chloroplast rDNA units of C. reinhardii.
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38
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Cramer JH, Rownd RH. Denaturation mapping of the ribosomal DNA of Saccharomyces cerevisiae. MOLECULAR & GENERAL GENETICS : MGG 1980; 177:199-205. [PMID: 6988667 DOI: 10.1007/bf00267430] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The thermal melting profile of purified Saccharomyces cerevisiae ribosomal DNA (rDNA) is biphasic indicating considerable intramolecular heterogeneity in base composition. The first phase of the transition, about 20% of the total hyperchromic shift, has a Tm of 80.6 degrees C and the second phase has a Tm of 87.3 degrees C, corresponding to GC contents of 28 and 44%, respectively. The Tm of the nonribosomal nuclear DNA, called alpha DNA, is 85.7 degrees C. This heterogeneity in GC distribution in the rDNA is also reflected in its denaturation map. A denaturation map of the 5.6 X 10(6) dalton rDNA SmaI restruction fragment, which represents monomer units of the rDNA, shows that specific regions of the repeating unit denature more readily than the remainder and apparently have a significantly higher AT content. By aligning the rDNA denaturation map with the restriction endonuclease map, we have been able to determine that the AT-rich segments are localized in the transcribed and nontranscribed spacer regions of the rDNA repeating unit. Buoyant density determinations of individual rDNA restriction fragments corroborate the locations of AT-rich regions. A denaturation map of the tandem repeating units in higher molecular weight rDNA has also been constructed and compared with the map of the SmaI fragment. The results show that the repeating units are uniform in size, that they are not separated by large heterogeneous regions, and that they are arranged in head-to-tail array.
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Ursic D, Davies J. A cold-sensitive mutant of Saccharomyces cerevisiae defective in ribosome processing. MOLECULAR & GENERAL GENETICS : MGG 1979; 175:313-23. [PMID: 392231 DOI: 10.1007/bf00397231] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Cold-sensitive mutants of Saccharomyces cerevisiae isolated by tritium suicide were screened for defects in ribosome biosynthesis. The biochemical defects of mutant dip-1 (defective in processing) were characterized; it is defective in ribosome biosynthesis at the level of production of the primary 35S transcript. At restrictive conditions mutant dip-1 accumulates abnormal rRNA in addition to wild-type rRNA. In the mutant the first observable transcription product was a 14SRNA species which had sequence homologies to 18S rDNA and was the major rRNA component of the 40S ribosomal subunit. In addition, the ribonucleoprotein particles of dip-1 harbored RNA molecules with homologies to yeast rDNA which comprises the spacer region between 18S and 25S rDNA cistrons. Possible causes for the defective production of rRNA and its assembly into subunits are discussed.
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41
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Petes TD, Smolik-Utlaut S. Evidence that the ribosomal DNA genes of yeast are not on chromosome I. MOLECULAR & GENERAL GENETICS : MGG 1979; 175:187-93. [PMID: 390314 DOI: 10.1007/bf00425535] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Several workers have reported that most of the ribosomal DNA genes (rDNA) of the yeast Saccharomyces cerevisiae are located on chromosome I. More recently, data indicating that the yeast rDNA genes are located on chromosome XII has been presented. In this report, we present additional evidence indicating that most of the yeast rDNA genes are not on chromosome I. Starting from a diploid yeast strain, we isolated ten strains which were monosomic (2n-1) for chromosome I. We found that each of these ten strains contained two copies of the rDNA-containing chromosome. In addition, we show that the earlier evidence indicating that the yeast rDNA genes were on chromosome I cannot be explained by a difference in the yeast strains which were used in the different experiments.
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42
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Free SJ, Rice PW, Metzenberg RL. Arrangement of the genes coding for ribosomal ribonucleic acids in Neurospora crassa. J Bacteriol 1979; 137:1219-26. [PMID: 155688 PMCID: PMC218304 DOI: 10.1128/jb.137.3.1219-1226.1979] [Citation(s) in RCA: 118] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
We have cloned and characterized Neurospora crassa ribosomal deoxyribonucleic acid (rDNA). The rDNA is found as a tandemly repeated 6.0-megadalton sequence. We have mapped a portion of the rDNA repeat unit with respect to its sites for 13 restriction endonucleases and defined those regions coding for the 5. 8S, 17S, and 26S ribosomal ribonucleic acids (rRNA's). We have also isolated several clones containing 5S rRNA sequences. The 5S rRNA coding sequences are not found within the rDNA repeat unit. We found that the sequences surrounding the 5S rRNA coding regions are highly heterogeneous.
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43
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Dawid IB, Wahli W. Application of recombinant DNA technology to questions of developmental biology: a review. Dev Biol 1979; 69:305-28. [PMID: 376374 DOI: 10.1016/0012-1606(79)90294-x] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Nikolaev N, Georgiev OI, Venkov PV, Hadjiolov AA. The 37 S precursor to ribosomal RNA is the primary transcript of ribosomal RNA genes in Saccharomyces cerevisiae. J Mol Biol 1979; 127:297-308. [PMID: 372542 DOI: 10.1016/0022-2836(79)90331-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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45
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46
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Oyen TB, Saelid G, Skuladottir GV. Study of a haploid yeast strain with an unusually high rDNA content. III. Unequal meiotic segregation of the gamma-DNA fraction. BIOCHIMICA ET BIOPHYSICA ACTA 1978; 520:88-102. [PMID: 359052 DOI: 10.1016/0005-2787(78)90010-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
DNA from different strains of Saccharomyces cerevisiae has been fractionated in preparative Ag+/Cs2-SO4 density gradients. The results show that there are real differences in amount of the nuclear satellite component, the gamma-DNA, from one strain to the other. The gamma-DNA forms a homogeneous dense band that contains all the rDNA, and the amount of gamma-DNA estimated from the gradients can be correlated to amount of rDNA derived from rRNA-DNA hybridizations. By various crossings and sporulations we have obtained diploid and haploid strains with gamma-DNA contents ranging from 7 to 20% of the nuclear DNA. During meiosis, the amount of gamma-DNA appears to segregate in a pattern that indicates unequal crossing over as a possible mechanism for differences in gamma-DNA contents.
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47
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Philippsen P, Kramer RA, Davis RW. Cloning of the yeast ribosomal DNA repeat unit in SstI and HindIII lambda vectors using genetic and physical size selections. J Mol Biol 1978; 123:371-86. [PMID: 357736 DOI: 10.1016/0022-2836(78)90085-2] [Citation(s) in RCA: 115] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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48
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Philippsen P, Thomas M, Kramer RA, Davis RW. Unique arrangement of coding sequences for 5 S, 5.8 S, 18 S and 25 S ribosomal RNA in Saccharomyces cerevisiae as determined by R-loop and hybridization analysis. J Mol Biol 1978; 123:387-404. [PMID: 357737 DOI: 10.1016/0022-2836(78)90086-4] [Citation(s) in RCA: 161] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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49
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Meyerink JH, Retèl J, Raué HA, Planta RJ. Genetic organization of the ribosomal transcription units of the yeast Saccharomyces carlsbergensis. Nucleic Acids Res 1978; 5:2801-8. [PMID: 693320 PMCID: PMC342208 DOI: 10.1093/nar/5.8.2801] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The genetic organization of the multiple ribosomal transcription units (RTUs) on the genome of the yeast Saccharomyces carlsbergensis was studied by electron microscopy of purified ribosomal DNA hybridized to 26S rRNA using the R-loop technique (Thomas, M., White, R.L. and Davis, R.W. (1973) Proc. Natl. Acad. Sci. U.S. 73, 2294-2298). Plasmid pBR 322, the molecular weight of which is known, was used as a standard for converting contour length of double-stranded DNA into molecular weight. The 140 yeast RTUs were found to be arrayed in tandem repeats, each repeat containing at most 0.4 X 10(6) D (about 6% of the length of the RTU) of non-transcribed spacer DNA. The repeats, in turn, are arranged in a number of clusters separated by much longer stretches of non-ribosomal DNA.
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Nath K, Bollon AP. Restriction analysis of tandemly repeated yeast ribosomal RNA genes. MOLECULAR & GENERAL GENETICS : MGG 1978; 160:235-45. [PMID: 353488 DOI: 10.1007/bf00332967] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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