Showing papers by "Cold Spring Harbor Laboratory published in 1973"
TL;DR: It is proposed that at least two of the adenovirus 2 virion components are derived by the cleavage of higher molecular weight precursor polypeptides, which imply precursor-product relationships for these components.
Abstract: Analysis of (35)S-methionine-labeled extracts of adenovirus 2-infected KB cells revealed 22 virus-induced polypeptide components. Most proteins of the virion were easily detected in extracts of whole cells labeled for short periods between 15 and 30 h after infection; however, several virion components were conspicuously absent. Radioactivity appeared in two of these virion components during a chase in nonradioactive medium, and this appearance was paralleled by a decrease in the radioactivity associated with two nonvirion adenovirus-induced proteins, results which imply precursor-product relationships for these components. Comparison of one of the chasable adenovirus-induced components (designated P-VII; mass of 20,000 daltons) and the major core protein (VII; mass of 18,500 daltons) of the virion showed that they have four common methionine-containing tryptic peptides; P-VII has an additional methionine residue which is not found in the major core protein. We propose that at least two of the adenovirus 2 virion components are derived by the cleavage of higher molecular weight precursor polypeptides.
724 citations
TL;DR: The number of copies of viralDNA in DNA of cells transformed by adenovirus type 2 has been determined by following the kinetics of reassociation of 32P-labeled viral DNA in the presence of unlabeled DNA extracted from transformed and control cells.
263 citations
TL;DR: The further resolution of the products arising from digestion of linear λ DNA with the RI endonuclease into six discrete fragments are described, and their subsequent characterization and mapping along the λ genome are described.
Abstract: THE analysis of in vitro DNA-directed transcription and coupled transcription/translation is usually complicated by the very large number of products that are made from each DNA molecule. If smaller DNA molecules could be used, the analysis would be correspondingly easier. The discovery of several restriction endonucleases, each recognizing a small number of unique cleavage sites per DNA molecule, could lead to a much deeper analysis of the complex structure and function of DNA by making it possible to isolate homogeneous DNA segments of manageable size. One of these enzymes, the RTF RI endonuclease, has recently been characterized by Yoshimuri, who has shown that it introduces a limited number of cuts in λ DNA1; by sucrose gradient sedimentation Yoshimuri separated a faster-moving peak containing one unique DNA population of molecular weight 13 × 106 from a slower-moving peak consisting of smaller fragments of average molecular weight 3.8 × 106. We describe here the further resolution of the products arising from digestion of linear λ DNA with the RI endonuclease into six discrete fragments, and their subsequent characterization and mapping along the λ genome.
146 citations
TL;DR: Escherichia coli possesses a protein degradation system which can distinguish between normal and aberrant polypeptides, and this degradation system for abnormal proteins is as sensitive to inhibition of the cell's energy metabolism by substances such as cyanide as is protein synthesis.
Abstract: Escherichia coli possesses a protein degradation system which can distinguish between normal and aberrant polypeptides1–8. For example, whereas the enzyme β-galactosidase, coded by the z gene of the lac operon, is itself stable, all the polypeptides produced by nonsense mutations in its structural gene are rapidly degraded in vivo1, 3. This degradation system for abnormal proteins is as sensitive to inhibition of the cell's energy metabolism by substances such as cyanide as is protein synthesis (ref. 4; and B. Shineberg, unpublished observations). Clearly, it is of considerable interest to characterize this system, which we refer to as the Deg system; the genetic locus or loci for this system is denoted by deg.
144 citations
TL;DR: This work describes the partial purification of two stimulatory factors (SF-A and SF-B) which specifically stimulate the activity of RNA polymerase II in the presence of double-stranded DNA as template.
136 citations
TL;DR: Although most of the tryptic peptides corresponding to the major virion protein can be detected in the in vitro synthesized polypeptides, all of them also gave rise to other, non-matching, peptides.
132 citations
TL;DR: The agglutination of transformed cells by plant lectins reflects some of the altered surface properties of these cells and is reversible and is inhibited by N-acetylglucosamine, di-Nacetyl chitobiose and ovomucoid.
Abstract: SURFACE changes on cell membranes are thought to play a significant role in malignant transformation. The agglutination of transformed cells by plant lectins reflects some of the altered surface properties of these cells1–3. Wheat-germ agglutinin (WGA) binds nearly equally to both normal and transformed cells4; however, with few exceptions, only transformed cells are agglutinated5–7. Agglutination by this lectin is reversible and is inhibited by N-acetylglucosamine, di-N-acetyl chitobiose and ovomucoid8.
127 citations
TL;DR: A method for visualizing in vitro synthesized RNA in extended form still attached to the DNA template is described, and the presence of a weak promotor at the right-hand end of the DNA is demonstrated.
96 citations
TL;DR: N-terminal β-galactosidase fragments are rapidly degraded in growing cells of Escherichia coli and mutations in the lon gene are sufficient to enhance the stability of these polypeptides.
Abstract: N-terminal beta-galactosidase fragments are rapidly degraded in growing cells of Escherichia coli. Mutations in the lon gene are sufficient to enhance the stability of these polypeptides.
72 citations
TL;DR: The amount of simian virus 40 (SV40) DNA present in various SV40-transformed mouse cell lines and "revertants" isolated from them was determined and there was no alteration in the pattern of the stable viral RNA species present in three concanavalin A- selected revertants, whereas in a fluorodeoxyuridine-selected revertant there appeared to be less viral-specific RNA present in the cells.
Abstract: The amount of simian virus 40 (SV40) DNA present in various SV40-transformed mouse cell lines and “revertants” isolated from them was determined. The number of viral DNA copies in the different cell lines ranged from 1.35 to 8.75 copies per diploid quantity of mouse cell DNA and from 2.2 to 14 copies per cell. The revertants had the same number of viral DNA copies per diploid quantity of mouse cell DNA as their parental cell lines. (However, they showed an increased number of viral DNA copies per cell due to their increased amount of DNA.) By using separated strands of SV40 DNA, the extent of each DNA strand transcribed into stable RNA species was determined for the transformed and “revertant” cell lines. From 30 to 80% of the “early” strand and from 0 to 20% of the “late” strand was present as stable RNA species in the cell lines tested. There was no alteration in the pattern of the stable viral RNA species present in three concanavalin A-selected revertants, whereas in a fluorodeoxyuridine-selected revertant there appeared to be less viral-specific RNA present in the cells.
61 citations
TL;DR: CYTOCHALASIN B, a drug isolated from Helminthosporium dematioideum, inhibits cytoplasmic cleavage and a number of processes concerned with cell movement.
Abstract: CYTOCHALASIN B, a drug isolated from Helminthosporium dematioideum, inhibits cytoplasmic cleavage and a number of processes concerned with cell movement. Mitosis is unaffected, so that cells treated with the drug become multinucleate1. Cytochalasin B is believed to interact either with microfilaments2 or directly with the plasma membrane3.
01 Jan 1973
TL;DR: Treatment of the SV40 transformed 3T3 cell line SV101 with colchicine permits the isolation of polyploid revertant sublines which have lower saturation densities than SV101, and normal SV40 has been recovered from these revertants.
Abstract: Treatment of the SV40 transformed 3T3 cell line SV101 with colchicine permits the isolation of polyploid revertant sublines Which have lower saturation densities than SV101. These low saturation density lines have also reverted to a high serum requirement for growth, and are unable to form colonies in methocel. Normal SV40 has been recovered from these revertants.
3T3 cells are more resistant to colchicine than SV3T3 cells at all cell densities. Colchicine revertants do not display a 3T3-like resistance to colchicine at low density, but do survive colchicine at confluent cell densities, presumably due to their increased contact inhibition.
TL;DR: Negative selection at low cell density in 1% calf serum or in 10% agamma‐depleted serum permits direct recovery of serum‐revertant sublines of SV101.
Abstract: SV101, the SV40-transformed subline of the mouse fibroblast line 3T3, is both serum- and density transformed, since it grows in both 1% and 10% calf serum, and grows beyond confluence in 10% calf serum. Negative selection at low cell density in 1% calf serum or in 10% agamma-depleted serum permits direct recovery of serum-revertant sublines of SV101. These sublines are unable to grow in 1% calf serum.
Although negative selection at high cell density in 10% calf serum is known to permit recovery of density-revertant sublines of SV101, most density-revertants are not serum-revertant. However, all serum-revertants isolated so far are density-revertant as well.
TL;DR: BSC-1 monkey kidney cells were en nucleated by two cycles of centrifugation in the presence of cytochalasin B and newly synthesized poliovirus was recovered from the enucleated populations.
Abstract: BSC-1 monkey kidney cells were enucleated by two cycles of centrifugation in the presence of cytochalasin B. The resulting populations contained 99.5 percent enucleated cells. After infection, newly synthesized poliovirus was recovered from the enucleated populations. Final virus yield per enucleated cell was about one-fifth the yield per infected untreated cell
TL;DR: The results suggest that the complementary strands of adenovirus type 2 DNA are replicated asynchronously, and the single-strand specific nuclease from Neurospora crassa released 25 to 30% of the radioactivity from replicating DNA.
TL;DR: By treating populations of simian virus 40 (SV40)-transformed 3T3 cells with concanavalin A, variants have been isolated which are resistant to the killing action of the lectin.
Abstract: By treating populations of simian virus 40 (SV40)-transformed 3T3 cells with concanavalin A, variants have been isolated which are resistant to the killing action of the lectin. The variants (i) resemble 3T3 cells morphologically and in some of their growth characteristics; (ii) are not agglutinated by high concentrations of concanavalin A or wheat germ agglutinin, but can be rendered agglutinable by treatment with low concentrations of trypsin; (iii) bind the same number of concanavalin A molecules as 3T3 or SV3T3 cells; (iv) cannot be transformed by SV40 and are resistant to focus formation after infection with murine sarcoma virus; (v) contain SV40-specific T antigen and RNA and; (vi) yield wild-type SV40 virus after heterokaryon formation with BS-C-1 cells.
TL;DR: The gene order of several independently isolated Mu prophages has been determined by deletion mapping and it can be inferred that the temperate bacteriophage Mu, which inserts randomly into the chromosome of E. coli, uses a specific site on its own DNA for integration.
TL;DR: The results suggest that most of the coupled polypeptide synthesis arises from early regions of λ DNA in vitro, and with a specificity that helped characterize some gene products.
TL;DR: The method for determining the prophage orientation described here can be used to orient a Mu prophages located at any site on the host chromosome and to produce F’ strains that transfer host markers in either direction from any location on the genome of E. coli.
01 Jan 1973
TL;DR: The amino acid compositions of VP4, VP5 and VP6 indicated that these proteins were not exclusively histones, and were likely to be related to capsid proteins of purified SV40 particles.
TL;DR: It is concluded that flee SV40-associated end has been concluded and the 8V40-assoeiated end0nucle~se is a non-specific,endonuelease ,occn~e.