Showing papers on "Gene published in 1970"

Molecular Biology of the Gene

Abstract: The long-awaited Fifth Edition of James D. Watson's classic text, Molecular Biology of the Gene, has been thoroughly revised and is published to coincide with the 50th anniversary of Watson and Crick's paper on the structure of the DNA double-helix. Though completely updated, the new edition retains the distinctive character of earlier editions that made it the most widely used book in molecular biology. Twenty-one concise chapters, co-authored by five highly respected molecular biologists, provide current, authoritative coverage of a fast-changing discipline. The completely new art is printed in full color for the first time. Divided into five parts, the first (Chemistry and Genetics) begins with an overview of molecular biology, placing the discipline in historical context and introducing the basic chemical concepts that underpin our description of molecular biology today. The second and third parts (Maintenance of the Genome and Expression of the Genome) form the heart of the book, describing in detail the basic mechanisms of DNA replication, transcription and translation. The fourth part of the book (Regulation) deals with how gene expression is regulated - from the examination of basic mechanisms that regulate gene expression in bacterial and eukaryotic systems, to a description of how regulation of gene expression lies at the heart of the process of development. Recent findings from sequencing whole genomes of several animals have revealed that they all share essentially the same genes. The last chapter in the regulation section looks at how changes in gene regulation can account for how different animals can be made up of the same genes. The final part of the book (Methods) deals with the techniques and methods used in molecular biology.

New RNA polymerase from Escherichia coli infected with bacteriophage T7.

Abstract: A new T7-specific RNA polymerase is found in T7 phage-infected cells It is the product of T7 gene I and is physically and biochemically distinct from the host cell RNA polymerase The synthesis of T7 RNA polymerase provides a direct explanation for the pleiotropic control of late T7 functions exerted by gene I

Genetic Control of the Cell-Division Cycle in Yeast, I. Detection of Mutants

Abstract: Time-lapse photomicroscopy has been utilized to detect temperature-sensitive yeast mutants that are defective in gene functions needed at specific stages of the cell-division cycle. This technique provides two types of information about a mutant: the time at which the defective gene function is normally performed, defined as the execution point, and the stage at which cells collect when the function is not performed, defined as the termination point. Mutants carrying lesions in three genes that control the cell-division cycle are described. All three genes, cdc-1, cdc-2, and cdc-3, execute early in the cell cycle at about the time of bud initiation, but differ in their termination points. Cells carrying the cdc-1 mutation terminate at the execution point, most cells ending up with a tiny bud that does not develop further. Cells carrying the cdc-2 mutation terminate at mitosis. Cells carrying the cdc-3 mutation are defective in cell separation but show no definite termination point since other processes of the cell cycle, such as bud initiation and nuclear division, continue despite the block in cell separation.

An improved method for determining codon variability in a gene and its application to the rate of fixation of mutations in evolution

Abstract: If one has the amino acid sequences of a set of homologous proteins as well as their phylogenetic relationships, one can easily determine the minimum number of mutations (nucleotide replacements) which must have been fixed in each codon since their common ancestor. It is found that for 29 species of cytochrome c the data fit the assumption that there is a group of approximately 32 invariant codons and that the remainder compose two Poisson-distributed groups of size 65 and 16 codons, the latter smaller group fixing mutations at about 3.2 times the rate of the larger. It is further found that the size of the invariant group increases as the range of species is narrowed. Extrapolation suggests that less than 10% of the codons in a given mammalian cytochrome c gene are capable of accepting a mutation. This is consistent with the view that at any one point in time only a very restricted number of positions can fix mutations but that as mutations are fixed the positions capable of accepting mutations also change so that examination of a wide range of species reveals a wide range of altered positions. We define this restricted group as the concomitantly variable codons. Given this restriction, the fixation rates for mutations in concomitantly variable codons in cytochrome c and fibrinopeptide A are not very different, a result which should be the case if most of these mutations are in fact selectively neutral as Kimura suggests.

Escherichia coli mutants with temperature-sensitive synthesis of DNA.

Abstract: Seven mutants of E. coli with temperature-sensitive synthesis of DNA have been isolated. Synthesis of RNA, protein and DNA precursors does not appear to be directly affected. The mutants can be divided into at least two groups on the basis of their pattern of DNA synthesis, their ability to support phage growth at 41° and their genetic mapping. Mutants of the first group are heterogeneous in their pattern of DNA synthesis at 40°. Some mutants cease DNA synthesis abruptly upon transfer to 40° and any residual DNA synthesis is barely detectable. In others there is substantial residual synthesis at 40°. All these Group 1 mutants are alike, however, in that they support the growth of phage T4 but not Lambda at 41°. Two mutants with barely detectable residual DNA synthesis carry DNA mutations which have been mapped by P1 transduction and show about 72% linkage to the malB locus. It has not yet proved possible to map accurately the mutants showing substantial residual synthesis, and the possibility that these mutations are in a different gene(s) has not been excluded. A single mutant has been placed in a second group. Like some Group 1 mutants it synthesizes substantial amounts of DNA at 40° before synthesis stops. However, unlike them it supports the growth of T4 and Lambda at 41°. The DNA mutation maps near the leu locus. Certain properties of this mutant are consistent with the idea that initiation of DNA synthesis is temperature-sensitive in this strain.

Genetic Dissection of the Drosophila Nervous System by Means of Mosaics

Abstract: Given a mutant having abnormal behavior, the anatomical domain responsible for the deficit may be identified by the use of genetic mosaicism. Individuals may be produced in which a portion of the body is mutant male while the rest is normal female. In such sex mosaics, or gynandromorphs, the division line between normal and mutant parts can occur in various orientations. Mutants of five different genes (cistrons) on the X-chromosome of Drosophila melanogaster, having various abnormalities in visual function, have been tested by this method. All of these have been found to be autonomous, i.e., a mutant eye always functions abnormally, regardless of the amount of normal tissue present elsewhere, indicating that the primary causes of the behavioral deficits in these mutants are within the eye.

Developmental genetics of the lactate dehydrogenase isozymes of fish

Abstract: Three genes (A, B, and E) encoding lactate dehydrogenase (LDH) subunits are shown to be present in fish by: (1) molecular hybridization, (2) allelic variants at two loci, and (3) kinetic, physical, and immunochemical studies. The same studies reveal that the E4 isozyme is closely related to the B4 isozyme. The E4 isozyme is usually synthesized in the regions of the nervous system concerned with vision. However, in some species the E4 isozyme is found in non-neural tissues such as lens. The closely related B and E loci tend to simulataneously functional in the same retinal cells. The act of hatching by itself does not appear to act as the stimulus to E gene activation. The E subunit facilitates the assembly of A and B subunits into the same teramer. The developmental and tissue specificity of the function of the LDH E gene suggests that the distinctive physical properties and the kinetic behavior of the LDH E4 isozyme may play an important role in the metabolism of teleost vision.

Total Synthesis of the Gene for an Alanine Transfer Ribonucleic Acid from Yeast

Abstract: By exploiting the natural ability of polynucleotides to align by base pairing and using polynucleotide kinase and ligase, chemically synthesized segments have been combined into a double stranded DNA corresponding to the gene for the earliest characterized tRNA.

Mutations Affecting the Repressibility of Arginine Biosynthetic Enzymes in Sacchromyces cerevisiae

Abstract: A method is described for isolating mutants of Saccharomyces cerevisiae which have lost repressibility by exogenous arginine for ornithine transcarbamylase. Besides permeability mutants, three complementary classes of mutations were found: argRI, argRII and argRIII which are recessive and define three loci. No evidence for a linkage between any of these three loci or with the gene coding for ornithine transcarbamylase has been obtained. Strains bearing mutations at either of these loci cannot be distinguished on a phenotype basis: after growth on minimal medium, the l-ornithine carbamoyl transferase activity is twice that of the wild type strain; the mutations modify neither the growth rate nor the permeability to arginine. The mutations might affect the structure of an hetero-polypeptidic aporepressor. The level of ornithine transcarbamylase in diploids is proportional to the number of argF+ genes in regulated as well as in non-regulated cells.

Regulation of Repressor Expression in λ

Abstract: A new gene in bacteriophage λ is described. The product of this gene cro prevents expression of immunity and regulates the expression of those genes to the left of the immunity region. cro- mutants have been isolated and characterized.

Genetics of the Ability of the Hessian Fly, Mayetiola destructor, to Survive on Wheats Having Different Genes for Resistance

Abstract: The genetics of the ability of the Great Plains race and Races A and E of the Hessian fly, Mayetiola destructor (Say), to survive on wheat cultivars ‘Seneca’ and ‘Monon,’ which have different genes for resistance (antibiosis), was studied in 3 crossing experiments. Results of reciprocal crosses between Great Plains race (larvae cannot survive on either cultivar) and Race A (larvae survive on Seneca but not on Monon) and between Great Plains race and Race E (larvae survive on Monon but not on Seneca) showed that the ability of Race A to survive on Seneca and of Race E to survive on Monon are controlled by single recessive gene pairs. The F2 and backcross generations demonstrated that males transmit only maternally derived chromosomes and that paternally derived chromosomes are eliminated during spermatogenesis. Since the F1 males of reciprocal crosses bred as if they were homozygous for the genotype of their female parent, the phenotype of F2 and backcross progenies differed according to the direction of the cross between the F1 parents. In a test for allelism, the reciprocal crosses between Race A and Race E produced F1 progenies that were the phenotype of the Great Plains race. Therefore, the ability to survive on Seneca and the ability to survive on Monon are controlled by genes at different loci and not by alleles of the same gene. Then the genie systems of the insect and host are complementary since there is a gene-for-gene relationship, and each resistant gene in wheat has a complementary gene for survival in the insect.

Isolation and genetic analysis of temperature-sensitive mutants of B. subtilis defective in DNA synthesis.

Abstract: Fifty temperature-sensitive mutants defective in DNA synthesis at high temperature have been identified among 655 temperature-sensitive mutants isolated at random from a mutagenised population of B. subtilis. They are distributed in a non-random fashion in 9 genetic linkage groups, located in different regions of the B. subtilis genome. It is suggested that at least 14 genes are involved in B. subtilis DNA replication.

Localization of 5S RNA Genes on Drosophila Chromosomes by RNA-DNA Hybridization

Abstract: [ 3H ] RNA with a high specific activity was prepared from larvae of Drosophila melanogaster grown 4 days in contact with [ 3H ] uridine. Purified tritiated 5 S RNA was annealed to the DNA of polytene chromosomes, which had been denatured in formamide. The 5 S RNA genes are placed within the region 56E-F of the right arm of chromosome 2. This localization was determined from autoradiographs, where the radioactivity from hybrids of [ 3H ] RNA and DNA was confined to the 56E-F segment.

Group-Specific Antigen Expression During Embryogenesis of the Genome of the C-Type RNA Tumor Virus: Implications for Ontogenesis and Oncogenesis

Abstract: Tests for the group-specific antigen of the C-type RNA tumor virus showed that mouse embryos of all strains tested, at some stage of development in utero, revealed detectable titers of group-specific antigen in one or more of their tissues; younger, rather than older, embryos were likely to be positive, particularly in those strains which normally reveal little or no expression of the RNA genome postnatally. The antigens were found in embryos of low-leukemia strains, free of infectious virus. These new findings support a previously stated hypothesis that the genome of RNA tumor viruses, mostly switched off for infectious virus expression, is vertically transmitted as part of the natural genetic apparatus of normal mouse cells. Since group-specific antigens have also been described in chick embryos and immunological tolerance to homologous group-specific antigens has been demonstrated in hamsters and cats as well as in mice and chickens, the hypothesis has been extended to include vertebrate cells in general. Finally, the high incidence and titers of the group-specific antigen suggest that the genes for RNA tumor virus, which later in life act as determinants of cancer, may be important also as gene determinants in the developing embryo.

Evidence for Control of Synthesis of the Variable Regions of the Heavy Chains of Immunoglobulins G and M by the Same Gene

Abstract: Previous work indicated that the light chains of a monotypic immunoglobulins G2-K and M-K from a single patient (Ti1) are identical. Our present data show that the monotypic immunoglobulins G and M share idiotypic determinants not present in their isolated light chains or in any of a large number of other immunoglobulins tested, and that amino acid sequences of the first 27 residues from the NH2-terminal end of the γ- and μ-chains are identical. These results support the hypothesis that at least two genes control the synthesis of each heavy and light chain and suggest that the monotypic immunoglobulin G and monotypic immunoglobulin M of this patient share three of the four genes involved. It is proposed that, during normal immunoglobulin synthesis, different cells of a single clone synthesize immunoglobulins M and G, and that the light chains and the variable segments of the heavy chains of the proteins of the two classes are identical within the clone. A genetic switching mechanism is suggested.

Structural Alteration of RNA Polymerase during Sporulation

Abstract: RNA polymerase from sporulating cells of B. subtilis has a subunit structure different from the vegetative enzyme. This alteration of RNA polymerase may be responsible for the turn-off of vegetative genes during spore formation.

Somatic translocation of antibody genes.

Abstract: A review of the structural and genetic properties of the immunoglobulins suggests that somatic recombination is fundamental in the selective immune response.

Enzyme evolution: generation of a bifunctional enzyme by fusion of adjacent genes.

Abstract: Two genes encoding distinct enzymes have been functionally fused by mutation. After fusion, the two genes act as one and produce a single polypeptide chain responsible for both catalytic activities.

Mitochondrial malate dehydrogenase and malic enzyme: Mendelian inherited electrophoretic variants in the mouse.

Abstract: Malate dehydrogenase and malic enzyme each possess supernatant and mitochondrial molecular forms which are structurally and genetically independent. We describe electrophoretic variants of the mitochondrial enzymes of malate dehydrogenase and malic enzyme in mice. Progeny testing from genetic crosses indicated that the genes which code for mitochondrial malate dehydrogenase and malic enzyme were not inherited maternally but as independent unlinked nuclear autosomal genes. The locus for mitochondrial malic enzyme was located on linkage group I. Linkage analysis with a third mitochondrial enzyme marker, glutamic oxaloacetic transaminase, showed that the nuclear genes which code for the three mitochondrial enzymes were not closely linked to each other. This evidence suggests that clusters of nuclear genes coding for mitochondrial function are unlikely in mice.

Linkage between the Poly-L-Lysine Gene and the Locus Controlling the Major Histocompatibility Antigens in Strain 2 Guinea Pigs

Abstract: The data presented demonstrate linkage between the major histocompatibility locus of inbred strain 2 guinea pigs and a „specific immune response gene,” the PLL gene, which controls responsiveness to poly-L-lysine and hapten conjugates of this polypeptide in these animals. This finding extends to another species and to a different immune system the linkage observed in mice between the H2 locus and specific immune response genes at the Ir-1 locus. The general significance of the linkage of specific immune response genes to histocompatibility loci is discussed.

Mutants of Streptomyces coelicolor defective in sporulation.

Abstract: Surmmary Sporulation-defective mutants were isolated on the basis of altered colonial coloration. The mutants were classified into a number of morphological classes by means of phase-contrast and electron microscopy. Some mutants lacking sporulation septa, the special septa that lead to spore delimitation and separation in the wild-type, or differing from the wild-type in the spacing of such septa, were subjected to genetic analysis. This has so far revealed two, and possibly three, genes concerned with the formation and spacing of sporulation septa.