Showing papers on "Genome published in 1974"
TL;DR: Chemical analysis and a study of renaturation kinetics show that the nematode, Caenorhabditis elegans, has a haploid DNA content of 8 x 10(7) base pairs (20 times the genome of E. coli).
Abstract: Chemical analysis and a study of renaturation kinetics show that the nematode, Caenorhabditis elegans, has a haploid DNA content of 8 x 10(7) base pairs (20 times the genome of E. coli). Eighty-three percent of the DNA sequences are unique. The mean base composition is 36% GC; a small component, containing the rRNA cistrons, has a base composition of 51% GC. The haploid genome contains about 300 genes for 4S RNA, 110 for 5S RNA, and 55 for (18 + 28)S RNA.
552 citations
TL;DR: Evidence is presented that the mitochondrial genome is inherited maternally in mammals too, unlike chromosomal genes, which are inherited biparentally.
Abstract: EUKARYOTIC cells contain a class of cytoplasmic DNA molecules which are found only within the mitochondria, where they replicate and are transcribed (for a general review see ref. 1). This mitochondrial DNA (mtDNA) constitutes the ‘mitochondrial genome’ and carries genetic information essential to mitochondrial function. In view of its extranuclear location, it is not surprising that inheritance of the mitochondrial genome is not governed by the same rules that apply to chromosomal genes. For fungi2–7 and amphibians8 there is evidence that the mitochondrial genome of an individual is derived solely from the maternal parent (in contrast to chromosomal genes, which are inherited biparentally). We present here evidence that the mitochondrial genome is inherited maternally in mammals too.
508 citations
TL;DR: Persistence of the viral DNA from preimplantation stages to adult life may provide a new tool for experimental investigation of vertical transmission and expression of tumor viruses.
Abstract: Explanted mouse blastocysts were microinjected in the blastocoel cavity with simian virus 40 (SV40) viral DNA. After surgical transfer to the uteri of pseudopregnant surrogate mothers, approximately 40% of the blastocysts developed to term and became healthy adults without apparent tumors at 1 year of age. Molecular hybridization tests for the presence of SV40-specific DNA sequences were conducted on DNA extracted from various organs of these animals. Between 0.5 and 13 SV40 genome equivalents per diploid mouse DNA value were found in some organs of approximately 40% of the adult survivors; this represents a substantial augmentation of the amount administered per embryo. The results are consistent with the working hypothesis that the SV40 DNA may have been integrated into the host genome; alternatively, the viral DNA may have replicated as an extrachromosomal entity or by lytic infection in a few permissive cells. Persistence of the viral DNA from preimplantation stages to adult life may thus provide a new tool for experimental investigation of vertical transmission and expression of tumor viruses.
406 citations
TL;DR: Three exceptional cell lines have been tested for the presence of the Epstein-Barr virus genome by nucleic acid hybridization (complementary RNA) and virus-determined nuclear antigen tests and two clearly had characteristics of B-cells (bone-marrow-derived).
Abstract: Three exceptional cell lines have been tested for the presence of the Epstein-Barr virus genome by nucleic acid hybridization (complementary RNA·DNA) and Epstein-Barr virus-determined nuclear antigen tests. Two lines were derived from Swedish lymphoma cases and one from an African Burkitt-like lymphoma biopsy that was negative for Epstein-Barr virus DNA and the virus-determined nuclear antigen. All three lines apparently lacked the viral genome. Two of the three lines clearly had characteristics of B-cells (bone-marrow-derived).
303 citations
300 citations
TL;DR: Apart from the demonstration of interand intraclonal heterogeneity as one of the basic features of mitochondrial crosses, reminiscent of course of the heterogeneity in burst size and composition in bacteriophages crosses, this “individualistic” approach has not as yet yielded any substantial insights into the mechanism of mitochondrial genetics.
Abstract: HE last few years have witnessed the accumulation of a considerable body experimental data dealing with the isolation of mitochondrial mutants in yeast conferring resistance to various inhibitors and with the results of two, three or four factor crosses using these mutants as genetic markers. All these results can be classified as belonging to two types of experimental approaches: one based essentially on an analysis of the progeny of an individual cell heterozygous for mitochondrial genetic markers and the second based essentially on an analysis of the progeny of a population of cells heterozygous for mitochondrial genetic markers. The first approach is exemplified by the work of LINNANE et al. 1968; THOMAS and WILKIE 1968; COEN et al. 1970; SAUNDERS et al. 1971 ; LUKINS et al. 1973; WILKIE and THOMAS 1973; the second by that of COEN et al. 1970; BOLOTIN et al. 1971; KLEESE, GROTBECK and SNYDER 1972 a and b; RANK and BECHHANSEN 1972; AVNER et al. 1973; AVNER and GRIFFITHS 1973; HOWELL et al. 1973; RANK 1973; WAKABAYASHI and KAMEI 1973; WOLF, DUJON and SLONIMSKI 1973; NETTER et al. 1974; COEN et al. (in preparation). At the very start of this period of mitochondrial genetics it became apparent that individual zygotic clones issued from a cross of two mitochondrially pure lines may behave quite differently from one another with respect to the types and proportions of the mitochondrial genotypes they give rise to (COEN et al. 1970). Pedigree analyses performed since have shown that not only are the proportions of different cell types variable from clone to clone but also their order of appearance (LUKINS et al. 1973; WILKIE 1973). Apart from the demonstration of interand intraclonal heterogeneity as one of the basic features of mitochondrial crosses, reminiscent of course of the heterogeneity in burst size and composition in bacteriophages crosses, this “individualistic” approach has not as yet yielded any substantial insights into the mechanism of mitochondrial genetics. The “population” approach is based on what COEN et al. (1970) have called a standard cross and has been adopted with no or only minor modifications by several authors (BOLOTIN et al. 1971; KLEESE, GROTBECK and SNYDER 1972 a and b; RANK and BECH-HANSEN 1972; SUDA and UCHIDA 1972; AVNER and GRIFFITHS 1973; AVNER et al. 1973; HOWELL et al. 1973; RANK 1973; TREMBATH et al. 1973; WAKABAYASHI and KAMEI 1973; WOLF, DUJON and SLONIMSKI 1973; NETTER et al. 1974 and COEN, in prep.). The standard cross is performed in such a way that (1) a sample of diploid cells randomly collected at the end of the cross should
248 citations
TL;DR: Fragments of DNA from derivatives of phage λ having either one or two targets for R.EcoRI have been joined in new combinations to give biologically active phage genomes.
Abstract: Fragments of DNA from derivatives of phage λ having either one or two targets for R.EcoRI have been joined in new combinations to give biologically active phage genomes. These include two classes of deletion mutants; in one, only the DNA between the targets is deleted, but in the second the deletions are more extensive. Other fragments of DNA have been inserted into these phage chromosomes.
222 citations
01 Jan 1974
TL;DR: The discovery by Gomatos and Tamm (1963a) that reovirus RNA is double-stranded caused great interest since, although double-Stranded RNA was at that time under active investigation as the replicative form of viral genomes consisting of single- Stranded RNA, it provided the first source of stable double- stranded RNA.
Abstract: The discovery by Gomatos and Tamm (1963a) that reovirus RNA is double-stranded caused great interest since, although double-stranded RNA was at that time under active investigation as the replicative form of viral genomes consisting of single-stranded RNA, it provided the first source of stable double-stranded RNA. Equally significant was the subsequent demonstration that the reovirus genome consists of a unique set of several distinct molecules; this upset the previously held notion that the genomes of all viruses consist of a single nucleic acid molecule.
131 citations
TL;DR: Serial passage of simian virus 40 (SV40) at high multiplicity of infection leads to the emergence of variants with deleted, substituted, and/or duplicated DNA.
Abstract: Serial passage of simian virus 40 (SV40) at high multiplicity of infection leads to the emergence of variants with deleted, substituted, and/or duplicated DNA. Individual variants have been cloned by selective complementation with temperature sensitive SV40 mutants, or nonselectively by coinfection of cells with wild-type helper virus. In each case, the presence of variants was detected by the appearance of discrete short viral genomes in infected cell lysates. Such short genomes, isolated by agarose gel electrophoresis, were shown to be specifically altered by comparing the electrophoretic pattern of their DNA fragments produced by Haemophilus influenzae restriction endonuclease with the pattern of fragments from parental DNA. In addition to defective variants, one infectious variant that had an additional segment of DNA within its genome was isolated.
131 citations
TL;DR: Mice of a non-virus-yielding strain made partially congenic for the AKR virus-inducing locus Akv-1 contained the complete virus genome, confirming that this locus consists of structural genes of the virus.
Abstract: Utilizing a single-stranded [3H]DNA probe highly representative of AKR viral 70S RNA, we have performed association kinetics experiments with cellular DNA in vast excess from 3 high-, 5 low- and 4 non-virus-yielding mouse strains. Our hybridization studies indicate that in the strains so far tested, the complete genome of the AKR-type MLV is present in the DNA of the embryos of both high- and low-virus-yielding mouse strains, while DNA of non-virus strains contains only a part of the genome. Furthermore, at least two populations of virus-specific DNA sequences can be identified (more abundant and less abundant species) according to their rate of association. Low-virus-yielding mouse strains contain a smaller number (1-2 copies) of the less abundant species, and thus a lower number of complete viral genome than do high-virus strains (3-4 copies). Non-virus-yielding strains are lacking these less abundant sequences in their genome. DNA from wild Mus musculus also contained viral sequences, the sample tested showing association kinetics identical to the non-virus-producing strains. Thus there is a good correlation between completeness of the AKR-type MLV genome in cellular DNA and the capacity of the cells to release AKR-type MLV. Mice of a non-virus-yielding strain made partially congenic for the AKR virus-inducing locus Akv-1 contained the complete virus genome, confirming that this locus consists of structural genes of the virus.
129 citations
TL;DR: Single-strand DNA copies of the polysome-associated messenger RNA of growing Friend cells (clone M2) have been synthesized and almost all of the DNA copies represent mRNA sequences which have been transcribed from the non-repetitive region of the genome.
TL;DR: It is postulated that the hybridization of mouse nondividing cells with human cancer cells could permit the identification of the human "oncogenic" chromosome(s) present inhuman cancer cells, since such chromosome should be retained by the totality of the mouse-human hybrid cells.
Abstract: Fusion of mouse peritoneal macrophages with SV40-transformed human cells, deficient in hypoxanthine guanine phosphoribosyltransferase, resulted in the formation of transformed somatic cell hybrids which contained, without exception, the human chromosome 7 carrying the SV40 genome. It is postulated that the hybridization of mouse nondividing cells with human cancer cells could permit the identification of the human "oncogenic" chromosome(s) present in human cancer cells, since such chromosome(s) should be retained by the totality of the mouse-human hybrid cells.
TL;DR: The average mitochondrion in these cells contains four mitochondrial genomes in both the haploid and the diploid, so the effect of nuclear gene dosage on the regulation of mitochondria is assessed.
Abstract: In order to assess the effect of nuclear gene dosage on the regulation of mitochondria we have studied serial sections of a set of isogenic haploid and diploid cells of Saccharomyces cerevisiae, growing exponentially in the absence of catabolite repression, and determined the amount of mitochondrial DNA per cell. Mitochondria accounted for 14% of the cytoplasmic and 12% of the total cellular volume in all cells examined regardless of their ploidy or their apparent stage in the cell cycle. The mean number of mitochondria per cell was 22 in the diploid and 10 in the haploids. The volume distribution appeared unimodal and identical in haploids and diploids. The mitochondrial DNA accounted for 12.6 ± 1.2% and 13.5 ± 1.3% of the total cellular DNA in the diploid and haploid populations, respectively. These values correspond to 3.6 x 10-15 g, 2.2 x 109 daltons, or 44 genomes (50 x 106 daltons each) per haploid and twice that per diploid cell. On this basis, the average mitochondrion in these cells contains four mitochondrial genomes in both the haploid and the diploid.
TL;DR: This chapter summarizes the different modes of particle heterogeneity that have been described and the methods suited for the detection and separation.
Abstract: Publisher Summary If a viral genome consists of two or more nucleic acid molecules of different length, which are separately encapsidated, the resulting particles are likely to differ in sedimentation rate but will not necessarily differ in size and buoyant density. The different classes of particles, which are called the components of the virus, can be separated by physical means. This chapter summarizes the different modes of particle heterogeneity that have been described and the methods suited for the detection and separation. If the size of the capsid is adapted to the size of the genome parts, the particles can be separated by electrophoresis in sieving media provided that an adequate pore size can be found and by sedimentation in density gradients. Since the RNA:protein ratio, and thus the buoyant density, does not differ appreciably, the particles cannot be separated by banding in equilibrium gradients. Tubular (tobraviruses) and bacilliform viruses (alfalfa mosaic virus) as well as spherical viruses (tobacco streak virus, pea enation mosaic virus) belong to this class. The particles of como- and nepoviruses do not differ in size, and thus cannot be separated by electrophoresis in sieving media, but they sediment and band differently. Separation of the parts of the genome can only be accomplished after the extraction of the RNA's. It is conceivable that viruses exist that have genome parts of the same length. The nepovirus tomato ring-spot virus approaches this situation. In the animal DNA virus, adeno-associated virus the complementary strands are present in different particles. In preparations of bromo- and cucumoviruses, a similar RNA is found encapsidated together with the smallest part of the genome.
TL;DR: Thiamineless mutants of Arabidopsis were corrected by treating the seeds with DNA preparations from various bacteria, and possible mechanisms for this are discussed.
Abstract: Avery’s [1] classical experiments showed that it was possible to influence cell function in procaryotes by the addition of exogenous genetic information. Analysis demonstrated that bacteria can take up DNA and integrate it into their genome by genetic recombination (see A. Tomasz, this book).
TL;DR: It is shown by direct physical means, that the amount of terminal repetition in P22 phage DNA is a direct function of the genome size, as predicted from the model for circular permutation and terminal repetition suggested by Streisinger et al .
TL;DR: In the ten strains tested, there is a good correlation between completeness of the genome of AKR-type murine leukemia virus in cellular DNA and the capacity of the cells to release infectious AKR -type murines leukemia virus.
Abstract: Studies with a single-stranded DNA probe complementary to the RNA of mouse-tropic AKR murine leukemia virus indicate that the complete genome of the AKR-type murine leukemia virus is present in the DNA of high- and low-virus-yielding mouse strains, while DNA of non-virus-yielding strains contains only a part of the genome. Furthermore, in those strains where the genome is complete, two populations of virus-specific DNA sequences can be identified (more abundant and less abundant species) according to their rate of association with the probe. Low-virus-yielding mouse strains contain fewer copies of the less abundant species and, consequently, fewer complete viral genomes than do high-virus-yielding strains. Thus, in the ten strains tested, there is a good correlation between completeness of the genome of AKR-type murine leukemia virus in cellular DNA and the capacity of the cells to release infectious AKR-type murine leukemia virus. Moreover, the number of complete viral genomes correlates with the frequency of infectious virus production by virus-positive strains. DNA from wild Mus musculus also contained viral sequences, the sample tested showing reassociation kinetics identical to the non-virus-producing strains.
TL;DR: In this paper, the deletions were mapped genetically, making use of their effect on plaque morphology, and by electron microscopy of DNA heteroduplexes to T2, a T2 T4 hybrid, and T4 wild type.
TL;DR: Despite the aforementioned obstacles to the study of organelle genetics, experi ments with the yeast Saccharomyces cerevisiae and the green alga Chlamydomonas reinhardtii are beginning to yield important insights into the genetics of mito chondria and chloroplasts respectively.
Abstract: An understanding of the rules governing the inheritance of chloroplast and mito chondrial genes has been slow in coming despite the isolation of presumptive plastid mutants as long ago as 1909 ( 1 , 2) and mitochondrial mutants over two decades ago (3, 4). Several reasons can be cited. First, until the discovery of unique species of chloroplast DNA in 1963 (5, 6) and mitochondrial DNA (mitDNA) at about the same time (7) there was no physical evidence for hereditary carriers in chloroplasts and mitochondria. Hence, specific mutations have been convincingly associated . with organelle DNA only recently. Second, the paucity of well-defined, phenotypi cally distinguishable organelle gene markers has posed a serious problem in all but a few organisms. Third, even in those organisms where suitable markers are avail able unique experimental problems arise because one cannot directly score the phenotype of the organelle carrying a specific mutation but only the phenotype of the cell within which the organelle resides. Furthermore, it is difficult to control the input and overflow of organelle genomes in a cross. One is tempted to make an analogy to a phage cross in which neither the average multiplicity of infection, average burst size, nor frequency of phenotypically different progeny phages can be measured directly. Despite the aforementioned obstacles to the study of organelle genetics, experi ments with the yeast Saccharomyces cerevisiae and the green alga Chlamydomonas reinhardtii are beginning to yield important insights into the genetics of mito chondria and chloroplasts respectively. This review is devoted to a discussion of these experiments. The specific topics to be considered include the evidence that genes are localized in the chloroplast of Chlamydomonas and the mitochondrion of Saccharomyces, segregation and recombination of organelle genes, genetic mapping and the formal models underlying the chloroplast and mitochondrial genetic maps, and finally a comparison of the organelle genetic systems of Chlamydomonas and Saccharomyces.
TL;DR: The size and nucleotide sequence complexity of the Bombyx mori genome has been determined from the kinetics of reassociation of its DNA and compares favorably with the DNA content of haploid B. mori spermatids and mature sperm determined cytophotometrically by Rasch (1973).
Abstract: The size and nucleotide sequence complexity of the Bombyx mori genome has been determined from the kinetics of reassociation of its DNA. Nonrepeated DNA comprises 55% of the genome, and the remainder is divided equally between sequences repeated roughly 500 and 50000 times. Non-repeated sequence DNA virtually free of repeated sequences was prepared by partial reassociation and subsequent fractionation on hydroxyapatite. The nucleotide sequence complexity of this component was determined relative to DNA from B. subtilis and E. coli. After correction for the size of the repeated sequence fraction, the DNA content of the Bombyx mori genome was calculated to be 0.53±0.02×10−12 g. This value compares favorably with the DNA content of haploid B. mori spermatids and mature sperm determined cytophotometrically by Rasch (1973).
TL;DR: The extent of heteroduplex formation and duplex thermal stabilities suggest a scheme for the evolution of these species which agrees with taxonomic and genetic evidence.
Abstract: Reassociation kinetics of sheared denatured DNAs from wheat, barley, rye, and oats at 60 C in 0.18 cm Na+ indicate that approximately 80% of these genomes consist of repeated nucleotide sequences, using hydroxylapatite chromatography to detect reannealed DNA. The remaining DNA appears to consist of sequences present in only one or a few copies per haploid genome. Studies on heterologous duplexes formed in vitro between the repeated sequence DNA fractions from each of the species in turn indicate that many of the families of repeated sequences in these cereals evolved from common ancestral sequences. The extent of heteroduplex formation and duplex thermal stabilities suggest a scheme for the evolution of these species which agrees with taxonomic and genetic evidence. Further analyses of these parameters indicate that many quantitative changes in the chromosomal complement of repeated sequences have occurred during divergence of these species.
TL;DR: The genome of feline sarcoma-leukemia viruses, like that of RD-114 virus, is at least partly homologous to DNA from normal cats, suggesting that normal cats harbor endogenous genes coding for components of at least two classes of C-type viruses.
TL;DR: It was found that in monkey cells both the viral transcription and viral translation were reduced by the same rate by human interferon, which supports the hypothesis that the SV40 genome transcription is primarily affected by interferons.
TL;DR: It is proposed that the two to three fold difference in the ratio of mitochondrial DNA to nuclear DNA in stationary phase cells grown in the presence of glycerol compared to glucose reflects an increased number of mitochondrial genomes in derepressed mitochondria.
Abstract: Genetic crosses were made using strains of Saccharomyces cerevisiae which carried cytoplasmically inherited markers conferring resistance to erythromycin, oligomycin and chloramphenicol. The frequency of transmission of these mitochondrial loci to diploid progeny was found to be influenced by the physiological state of the haploid parents, and was not affected by the cis or trans configuration of the three resistance markers. No recombinational polarity was seen in any of the crosses. Growth of a haploid parental strain to stationary phase in a yeast extract peptone medium containing glycerol as a carbon source resulted in a high level of transmission of mitochondrial markers when crossed with a strain grown to stationary phase in the same medium but with glucose as carbon source. When cells were grown under the same conditions as those used in the genetic crosses they were found to contain more mitochondrial DNA relative to nuclear DNA when glycerol was used as a carbon source than when glucose was used. Two criteria were used to determine the amount of mitochondrial DNA present: i) incorporation of radioactive precursors into the different DNA species; and ii) measurement of the mass of DNA from amounts of ultraviolet-absorbing material at the appropriate buoyant densities in isopycnic CsCl gradients. It is proposed that the two to three fold difference in the ratio of mitochondrial DNA to nuclear DNA in stationary phase cells grown in the presence of glycerol compared to glucose reflects an increased number of mitochondrial genomes in derepressed mitochondria. This difference, by a “genome dosage” effect, could account for the variations in the genetic parameter of the frequency of transmission, i.e., strains grown with glycerol as a carbon source contain more mitochondrial genomes than glucose-grown strains and thus will contribute more mitochondrial markers to the zygote.
TL;DR: Complete transcripts of the genome of vesicular stomatitis virus Indiana strain have been used to hybridize to virion RNA to determine if there is RNA sequence homology among these viruses.
Abstract: Complete transcripts of the genome of vesicular stomatitis virus Indiana strain have been used to hybridize to virion RNA to determine if there is RNA sequence homology among these viruses. Cellular RNA from cells infected by each of these viruses has also been used for hybridization with the homologous or heterologous virion RNA. The results indicate that there is little exact sequence homology among these viruses.
TL;DR: In this paper, two defective adenovirus-simian virus 40 hybrids (Ad2++HEY and Ad2++LEY) were isolated and the structures of the DNA molecules in the two populations were examined using electron microscope heteroduplex methods.
TL;DR: One phage gene, A, has been shown to be necessary for the replication of ΦX174 double-stranded replicative form (RF) DNA1, although the host genes required have yet to be fully determined.
Abstract: ONLY one phage gene, A, has been shown to be necessary for the replication of ΦX174 double-stranded replicative form (RF) DNA1–3. The host genes required have yet to be fully determined although one host mutation, rep−3, prevents progeny RF synthesis4. Dissection of the characteristics of gene A has shown that it is (a) cis acting5; (b) necessary for the detection of a cis-related viral strand specific discontinuity in the parental RF6,7; (c) the region of the genome which contains the origin of DNA replication8, and (d) a gene from which two proteins, A and A′ (molecular weights 35,000 and 60-65,000, respectively) are synthesised9,10.
TL;DR: The distribution of heterochromatic regions in the chromosomes of diploid, tetraploid and hexaploid wheat showed that the B genome possesses characteristic large blocks as discussed by the authors.
Abstract: The distribution of heterochromatic regions in the chromosomes of diploid, tetraploid and hexaploid wheat shows that the B genome possesses characteristic large blocks. Though analyses of probable B genome donors indicate that Aegilops speltoides has a pattern of distribution of heterochromatin nearest to the B genome chromosomes, a polyphyletic origin of tetraploid wheat seems more plausible.