PubMed Health⌕ Search

Biomedical subjects

H Delius

Publications and source records attributed to H Delius.

At least 37 records · Page 2Linked to original sources
PubMed1986

Structure of gene and pseudogenes of human apoferritin H.

Ferritin is composed of two subunits, H and L. cDNA's coding for these proteins from human liver (1,2,3), lymphocytes (4) and from the monocyte-like cell line U937 (5) have been cloned and sequenced. Southern blot analysis on total human DNA reveals that there are many DNA segments hybridizing to the apoferritin H and L cDNA probes (1,2,4,6). In view of the tissue heterogeneity of ferritin molecules (7,8), it appeared possible that apoferritin molecules could be coded by a family of genes differentially expressed in various tissues (1,2). In this paper we describe the cloning and sequencing of the gene coding for human apoferritin H. This gene has three introns; the exon sequence is identical to that of cDNA's isolated from human liver, lymphocytes, HeLa cells and endothelial cells. In addition we show that at least 15 intronless pseudogenes exist, with features suggesting that they were originated by reverse transcription and insertion. On the basis of these results we conclude that only one gene is responsible for the synthesis of the majority of apoferritin H mRNA in various tissues examined, and that probably all the other DNA segments hybridizing with apoferritin cDNA are pseudogenes.

Apoferritins↗
PubMed1986

Inhibition of bacterial segregation by early functions of phage mu and association of replication protein B with the inner cell membrane.

Infection of Mu-sensitive bacteria with a recombinant lambda phage that carries the EcoRI.C fragment from the immunity end of wild type Mu DNA causes filamentous growth. Transmission electron microscopy revealed that the cell-division cycle was inhibited at, or prior to, the initiation of septation. The filamentation does not occur after infection of Mu-immune bacteria or after infection with a phage carrying the same EcoRI.C fragment, but with an IS1 insertion in gene B of Mu, showing that either gpB and/or some non-essential functions (e.g. kil) mapping downstream from the insertion are required for the inhibition of cell division. These data and previously published evidence suggest that in the "killing" of E. coli K12 by early Mu functions expressed from the cloned EcoRI.C fragment, two components have to be distinguished: one, a highly efficient elimination of plasmid DNA carrying the early Mu genes, and second, a series of interactions with host functions conducent to an inhibition of cell division. It is suggested that functions normally involved in the SOS reaction participate in the inhibition of cell division by early Mu functions. Infected bacteria synthesize the replication protein B (MR 33000) of Mu, which was found by cell fractionation experiments to be associated with the inner cell membrane. The role of this association for filamentous growth and for the integrative replication of the phage is discussed. The recombinant phage might be useful as a tool for the study of the E. coli cell division cycle.

Bacterial Proteins↗
PubMed1985

Molecular cloning and physical mapping of the genome of fish lymphocystis disease virus.

A defined and complete gene library of the fish lymphocystis disease virus (FLDV) genome was established. FLDV DNA was cleaved with EcoRI, BamHI, EcoRI/BamHI and EcoRI/HindIII and the resulting fragments were inserted into the corresponding sites of the pACYC184 or pAT153 plasmid vectors using T4 DNA ligase. Since FLDV DNA is highly methylated at CpG sequences (Darai et al., 1983; Wagner et al., 1985), an Escherichia coli GC-3 strain was required to amplify the recombinant plasmids harboring the FLDV DNA fragments. Bacterial colonies harboring recombinant plasmids were selected. All cloned fragments were individually identified by digestion of the recombinant plasmid DNA with different restriction enzymes and screened by hybridization of recombinant plasmid DNA to viral DNA. This analysis revealed that sequences representing 100% of the viral genome were cloned. Using these recombinant plasmids, the physical maps of the genome were constructed for BamHI, EcoRI, BestEII, and PstI restriction endonucleases. Although the FLDV genome is linear, due to circular permutation the restriction maps are circular.

Animals↗
PubMed1985

Separation of complementary strands of plasmid DNA using the biotin-avidin system and its application to heteroduplex formation and RNA/DNA hybridizations in electron microscopy.

A method for the separation of complementary strands with the help of the biotin-avidin system is described. Restriction fragments were terminally labeled at both ends with biotinylated nucleotides. The DNA was cut by a second restriction enzyme, and the fragments were bound to an avidin agarose column. The non-biotinylated strands were eluted with 0.1 M NaOH, and the biotin-labeled strands were subsequently released from the column by elution with 50% guanidine isothiocyanate/formamide. Contamination of the separated strands by complementary single strands was less than 4%.-Separated linear single strands of the vector pEMBL were prepared. On annealing with recombinant circular DNA a substitution loop is formed which provides position and orientation markers for the unambiguous electron microscopic analysis of heteroduplexes or hybrids formed with the inserted sequences. -The terminal biotin label was visualized by complex formation with a streptavidin-ferritin conjugate.

Avidin↗
PubMed1985

Isolation and characterization of the chicken cardiac myosin light chain (L-2A) gene. Evidence for two additional N-terminal amino acids.

The contractile proteins of striated muscle are encoded by multigene families and constitute an excellent system to investigate differentiation and developmental control of gene expression. Different forms of myosin light chains are expressed in skeletal muscle as well as in the myocard. To study the gene structure and molecular mechanisms underlying differential gene expression, the structural cardiac myosin light chain 2 (MLC-2A) gene was isolated from a chicken genomic DNA library. Restriction enzyme mapping, electron microscopic analysis, and partial sequencing revealed that the gene coding for the MLC mRNA of 700 nucleotides in length extends over 4.2 kilobases of DNA and is interrupted by 5 introns. Sequence analysis led to the detection of two codons for additional amino acids at the N terminus which were not reported to be present in the mature protein and are presumably removed post-translationally. These two amino acids, methionine and alanine, are coded on two separate exons split by the largest intron of the entire gene. Southern blot analysis of genomic chicken DNA indicates the presence of one MLC-2A gene per haploid chicken genome.

Amino Acid Sequence↗
PubMed1985

A putative transforming gene of Jijoye virus differs from that of Epstein-Barr virus prototypes.

The P3HR-1 strain of Epstein-Barr virus (EBV), a nontransforming clonal derivative of Jijoye (EBV), is characterized by a deletion of 6.6 kb involving part of the BamHI-W repeats and the adjacent region including the NotI repeats. In the transforming parental Jijoye virus this region differs from the corresponding regions in B95-8 or M-ABA virus. The HindIII-B fragments which carry this region from both Jijoye and prototype M-ABA (EBV) viruses have been cloned and subclones have been constructed which contain the left-hand part of HindIII-B from the HindIII to the BglII site (BglII-delta C fragment). By restriction enzyme analysis the inserts were found to be of equal size (6.3 kb) but to differ in their restriction enzyme pattern. Heteroduplexes formed under stringent conditions in the presence of T4 gene 32 protein revealed a substitution loop of 1750 +/- 200 nucleotides. Heteroduplex formation under nonstringent conditions showed that the substituted sequences are partially homologous to each other, with the regions of nonhomology confined to three distinct areas of 100 to 200 nucleotides. The partial homology observed between both regions indicates that they have evolved from a common ancestor. By hybridization of a Jijoye virus subclone containing only sequences of the substituted region to Northern blots a 2.8-kb polyadenylated transcript was detected indicating that the substituted region is expressed in Jijoye cells.

Cell Line↗
PubMed1985

Analysis of cosmids using linearization by phage lambda terminase.

A group of cosmid clones was isolated from the region of the mouse t complex and analysed by a rapid restriction mapping protocol based on linearization of circular cosmid DNA in vitro. A plasmid capable of producing high levels of phage lambda terminase was constructed and procedures for in vitro cleavage of cosmid DNAs were optimised. After linearization, the cosmids were partially digested with restriction enzymes, and either cos end was labelled by hybridization with radioactive oligos complementary to the cohesive end sequence, a step which we have described previously for clones in phage lambda (Rackwitz et al., 1984). High-resolution restriction maps derived by this method were used to identify and align the cosmids, to localise the position of repetitive sequences, and to interpret the results of electron microscopy heteroduplex experiments.

Animals↗
PubMed1985

Molecular cloning and physical mapping of the tupaia herpesvirus genome.

Purified virion DNA of about 200 kilobase pairs of tupaia herpesvirus strain 2 was cleaved with EcoRI or HindIII restriction endonuclease. Restriction fragments representing the complete viral genome including both termini were inserted into the EcoRI, HindIII, and EcoRI-HindIII sites of the bacterial plasmid pAT153. Restriction maps for the restriction endonucleases EcoRI and HindIII were constructed with data derived from Southern blot hybridizations of individual viral DNA fragments or cloned DNA fragments which were hybridized to either viral genome fragments or recombinant plasmids. The analysis revealed that the tupaia herpesvirus genome consists of a long unique sequence of 200 kilobase pairs and that inverted repeat DNA sequences of greater than 40 base pairs do not occur, in agreement with previous electron microscopic data. No DNA sequence homology was detectable between the tupaia herpesvirus DNA and the genome of murine cytomegalovirus, which was reported to have a similar structure. In addition, seven individual isolates of tupaia herpesvirus were characterized. The isolates can be grouped into five strains by their DNA cleavage patterns.

Animals↗
PubMed1985

Characterization of the DNA of canine adenovirus by restriction enzyme analysis.

The DNA of canine adenovirus (canAV 1, strain Behring H.c.c. 269) was characterized in detail. The molecular weight of canAV DNA was (20.1 +/- 0.1) x 10(6) daltons as determined by contour length measurements, and 19.9 x 10(6) daltons as determined by restriction enzyme analysis. A terminal protein was found to be covalently linked to the 5' ends of canAV DNA. Physical maps of viral DNA were constructed for BamHI, ClaI, SacI, SalI, and SmaI enzymes. Three international strains of canAV [American Type Culture Collection (ATCC) catalogue No. VR-800, VR-293, and VR-133] were analyzed under the same conditions. CanAV 1 (ATCC VR-133 and VR-293) had DNA cleavage patterns identical to the H.c.c. 269 strain, whereas the DNA cleavage pattern of canAV 2 (ATCC VR-800) was clearly different.

Adenoviridae↗
PubMed1978

Electron microscopic analysis of in vitro transcriptional complexes: mapping of promoters of the coliphage T5 genome.

Transcriptional complexes formed in vitro with coliphage T5 DNA as template were analyzed by electron microscopy and the number and location of starting sites utilized by E. coli RNA polymerase were determined. Of the 40 promoters characterized in this way, 6 map in the two terminal "pre-early" regions, 29 in the "early" and 5 in the "late" region. The direction of transcription within the different regions determined in this study agrees with earlier findings derived from RNA synthesized in vivo.

Coliphages↗
PubMed1978

Cloning of a restriction fragment of phage mu DNA coding for early functions.

The DNA of an E. coli K12 strain harboring ten wildtype Mu prophages was restricted with endonuclease EcoRI, and the fragments ligated into the plasmid vector pMB9. Upon transformation of a strain carrying a heat inducible (Mu cts62) prophage, one temperature-resistant transformant was isolated. This transformant strain harbors the hybrid plasmid pKN001, containing the EcoRI.C fragment of Mu DNA as shown by restriction and heteroduplex analysis. Stable transformants of pKN001 are immune to superinfection with phage Mu. Transformation of Mu sensitive bacteria with pKN001 results in killing of the recipients (10(-4) surviving bacteria). The killing function is not expressed upon transformation of Mu-immune (lysogenic) bacteria.

Cell Transformation, Viral↗
PubMed1978

The isolation of DNA from agarose gels by electrophoretic elution onto malachite green-polyacrylamide columns.

Electrophoretic elution of DNA coupled with direct adsorption onto malachite green-polyacrylamide columns was used to isolate double- and single-stranded DNA from agarose gels. Subsequently, DNA was eluted with a high salt buffer and filtered through Sephadex which permitted recovery of the DNA in a low salt buffer at concentrations suitable for heteroduplex analysis by electron microscopy. This method was tested by examining heteroduplexes formed from the isolated complementary single strands of T7 wild type DNA and a T7 deletion mutant. More than 80% of the reannealed molecules were intact heteroduplexes showing the deletion loop. Irradiation of single-stranded DNA with 254 nm light resulted in distorted, convoluted heteroduplexes while 366 nm light did not show this effect.

Coliphages↗
PubMed1978

Herpesvirus ateles DNA and its homology with Herpesvirus saimiri nucleic acid.

Analysis of the structural organization of Herpesvirus ateles DNA shows that two types of viral DNA molecules are encapsidated in virions: (i) M-genomes, which contain 74% light sequences (L-DNA, 38% guanine plus cytosine) and 26% highly repetitive heavy sequences (H-DNA, 75% guanine plus cytosine), and (ii) defective H-genomes, which consist exclusively of repetitive H-DNA. The structure of M-genomes from H. ateles consists of an L-DNA region of about 70 x 10(6) daltons inserted between H-DNA termini of variable length. M-genomes with a shorter H-DNA region at one end of the molecule have a long stretch of H-DNA at the other end, resulting in a total molecular weight of 89.8 +/- 8.5 x 10(6). Thus it resembles the structure of M-genomes of H. saimiri. H-DNA of the two independent H. ateles isolates, strains 810 and 73, reveals different patterns after cleavage with restriction endonuclease Sma I. H-DNA of H. ateles 810 appears to consist of identical tandem repeat units with a molecular weight of 1,035,000; the H-DNA repeat unit of strain 73 is shorter (930,000 molecular weight). Corresponding DNA sequences of the two H. ateles strains (810 and 73) are completely homologous in cross-hybridizations. However, a discrete nucleotide sequence divergence between these virus strains is detected by measuring melting temperatures (T(m)) of DNA hybrid molecules. Some homology exists between H. ateles and H. saimiri DNA. Hybridization of L-DNA from H. ateles with L-DNA from H. saimiri shows about a 35% homology between the respective L-DNA sequences; the resulting heteroduplex molecules show a decrease of T(m) by 13.5 degrees C, corresponding to about a 9% mismatching in cross-hybridizing parts of L-regions. Very little homology is found between H-DNA of H. ateles and H. saimiri.

Base Sequence↗
PubMed1978

Heterogeneity of Epstein-Barr virus. III. Comparison of a transforming and a nontransforming virus by partial denaturation mapping of their DNAs.

The DNAs of a transforming and a nontransforming Epstein-Barr virus strain, B95-8 AND P3HR-1, were compared by partial denturation mapping. B95-8 viral DNA showed a homogeneous denaturation pattern. In contrast, P3HR-1 viral DNA was heterogeneous, containing at least two classes of molecules, classified into groups A and B and present in a ratio of about 2:1 to 3:1. No evidence could be obtained that molecules from both groups A and B contain identical sequences present in different orientations as described for herpes simplex viral DNA. The majority of sequences present in B95-8 and in P3HR-1 viral DNA group A could be correlated by assuming that different sequences, about 12,000 base pairs long, were inserted or deleted, respectively, at different position of both viral genomes.

Adenine↗
PubMed1976

Single-stranded DNA structure and DNA polymerase activity in the presence of nucleic acid helix-unwinding proteins from calf thymus.

In the preceding articles we have described the isolation and some of the properties of two calf thymus proteins which bind selectively to single-stranded DNA and which appear analogous to previously isolated prokaryotic DNA-unwinding proteins. In the present work we demonstrate two further points of analogy. First, both the calf UP1 and the high salt eluting proteins form protein-rich complexes with single-stranded DNA, and hold this DNA in a rigid, extended conformation. Second, these proteins stimulate the calf thymus DNA polymerase-alpha; phage T4 gene 32-protein does not. The stimulation of a homologous DNA polymerase is characteristic of several prokaryotic DNA-unwinding proteins and is assumed to reflect their in vivo role in DNA synthesis.

Animals↗
PubMed1976

A partial denaturation map of herpes simplex virus type 1 DNA: evidence for inversions of the unique DNA regions.

Partial denaturation maps of 30 HSV-I DNA molecules have been obtained using a procedure designed to avoid possible hydrolysis of the DNA at alkalilabile bonds. From the denaturation pattern of the long unique DNA region these molecules were divided into two groups comprised of 16 and 14 molecules. Histogram plots relating the precentage denaturation to position on the DNA for these two groups were aligned in a manner appropriate to the HSV-I genome model. It was apparent that these groups had the orientation of the long region inverted with respect to each other. Similarly, from the denaturation maps of the short unique region, the molecules were divided into two groups each comprising 15 molecules. Alignment of the histogram plots of these groups indicated that the orientation of the short region was inverted in one group relative to the other. These partial denaturation data confirm the presence of four HSV-I genome arrangements resulting from the possible combinations of inversions of the two unique DNA regions.

DNA, Viral↗
PubMed1976

Multiple origins and circular structures in replicating T5 bacteriophage DNA.

Replicating T5 phage DNA was gently isolated using NaI density gradient centrifugation and examined by electron microscopy. At the beginning of phage DNA synthesis, linear unit-length T5 DNA molecules containing from one to four replicating "eye-loops" were consistently observed. Replication in these molecules was found to proceed bidirectionally from multiple, internal origins. A primary origin of replication is located near the center of the T5 genome, which does not coincide with the location of any of the nicks (single-strand breaks) found in mature T5 DNA. The initiation of replication at the various origins within an individual molecule does not appear to follow any definite temporal sequence. At later times in the infection, we have observed a significant number of circular T5 DNA molecules-both replicating and nonreplicating-whose average circumference is approximately the length of mature T5 DNA minus the terminal redundancy. The replicating circular molecules appear to be either in a theta configuration, a sigma configuration with the tails all being less than the length of the circle, or a combination of theta and sigma forms.

Coliphages↗