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Biomedical subjects

H Land

Publications and source records attributed to H Land.

At least 55 records · Page 3Linked to original sources
PubMed1983

Cellular oncogenes and multistep carcinogenesis.

Two dozen cellular proto-oncogenes have been discovered to date through the study of retroviruses and the use of gene transfer. They form a structurally and functionally heterogeneous group. At least five distinct mechanisms are responsible for their conversion to active oncogenes. Recent work provides experimental strategies by which many of these oncogenes, as well as oncogenes of DNA tumor viruses, may be placed into functional categories. These procedures may lead to definition of a small number of common pathways through which the various oncogenes act to transform cells.

Gene Expression Regulation↗
PubMed1982

Nucleotide sequence of cloned cDNA encoding bovine arginine vasopressin-neurophysin II precursor.

The sequence of a cDNA encoding the nonapeptide arginine vasopressin (AVP) and its carrier protein, neurophysin II (NpII) from bovine hypothalamus, proves that the 166-amino acid precursor molecule contains a signal peptide of 19 amino acids followed directly by AVP connected to NpII by a Gly-Lys-Arg sequence. The carboxy-terminal region of the precursor contains a naturally occurring glycopolypeptide of 39 amino acids which is separated from NpII by a single arginine residue.

Amino Acid Sequence↗
PubMed1981

5'-Terminal sequences of eucaryotic mRNA can be cloned with high efficiency.

A method for cloning mRNAs has been used which results in a high yield of recombinants containing complete 5'-terminal mRNA sequences. It is not dependent on self-priming to generate double-stranded DNA and therefore the S1 nuclease digestion step is not required. Instead, the cDNA is dCMP-tailed at its 3'-end with terminal deoxynucleotidyl transferase (TdT). The synthesis of the second strand is primed by oligo(dG) hybridized to the 3'-tail. Double-stranded cDNA is subsequently tailed with dCTP and annealed to dGMP-tailed vector DNA. This approach overcomes the loss of the 5'-terminal mRNA sequences and the problem of artifacts which may be introduced into cloned cDNA sequences. Chicken lysozyme cDNA was cloned into pBR322 by this procedure with a transformation efficiency of 5 x 10(3) recombinant clones per ng of ds-cDNA. Sequence analysis revealed that at least nine out of nineteen randomly isolated plasmids contained the entire 5'-untranslated mRNA sequence. The data strongly support the conclusion that the 5'-untranslated region of the lysozyme mRNA is heterogeneous in length.

Avian Myeloblastosis Virus↗
PubMed1981

Multiple mRNAs are generated from the chicken lysozyme gene.

We have determined the DNA sequence of a 770 bp Pst 1 fragment containing 450 nucleotides of the 5' flanking region of the chicken lysozyme gene. S1-nuclease mapping was performed to localize the 5' end of nuclear RNA containing lysozyme-specific sequences and of the mRNA. We present evidence that the 5' noncoding region of the chicken lysozyme mRNA is heterogeneous in length. The 5' termini of the different nRNAs map 29, 31 and 53 nucleotides upstream from their common initiation codon. The 5' ends of lysozyme-specific nuclear RNAs map at positions similar to that of the mRNA. AT-rich regions and sequences similar to the E. coli RNA polymerase recognition sequence are found around 30 and 70 nucleotides upstream from each of these 5' termini. The AT-rich regions differ, however, from the canonical Goldberg-Hogness box in that they do not contain the extremely conserved TATA sequence motif. Sequence comparison at the 5' end of the lysozyme, conalbumin and ovalbumin genes reveals only one region of partial homology, 140 nucleotides upstream from the mRNA start sites.

Animals↗
PubMed1979

Isolation and characterization of the chicken ovomucoid gene.

The chicken ovomucoid gene has been isolated by screening a chicken DNA library with a plasmid containing ovomucoid mRNA sequences. Twelve recombinant phages carrying ovomucoid mRNA sequences were isolated. Two of them, extending farthest into the 5' and 3' direction respectively, were characterized by restriction mapping and Southern hybridization as well as by electron microscopic analysis of hybrids between the cloned DNA and ovomucoid mRNA. Seven intervening sequences interrupt the ovomucoid mRNA sequence in chromosomal DNA. From these data a minimal size of 5.6 kb can be estimated for the length of the ovomucoid gene.

Animals↗
PubMed1979

Chicken lysozyme gene contains several intervening sequences.

The organization of the chicken lysozyme gene and its neighboring sequences was examined by a comparison of the restriction map of the lysozyme structural gene with the map of the lysozyme gene in genomic DNA. Chicken DNA was cleaved with restriction endonucleases and the DNA fragments were separated by agarose gel electrophoresis. After transfer of the fragments onto nitrocellulose filters, those fragments that contain lysozyme mRNA sequences were detected by hybridization of the filters to labeled probes generated from pls-1, a recombinant plasmid carrying the lysozyme structural gene. This analysis revealed the presence of at least three intervening sequences, two of which interrupt the protein coding region and one of which is located in the 3' untranslated region. When oviduct DNA and sperm DNA were compared, no difference was observed in the size and number of restriction fragments that contain either lysozyme or ovalbumin structural gene sequences.

Animals↗
PubMed1978

Cloning of chicken lysozyme structural gene sequences synthesized in vitro.

Double-stranded chicken lysozyme cDNA was synthesized from an oviduct mRNA fraction enriched for lysozyme mRNA. The ds-cDNA was inserted into the BamHI site of plasmid pBR322 using chemically synthesized DNA linker molecules containing the BamHI restriction endonuclease cleavage site. After bacterial transformation, colonies carrying lysozyme DNA were identified by hybridization with highly purified lysozyme cDNA. The 555 base pairs long cloned DNA fragment of one recombinant plasmid was isolated and characterized by restriction endonuclease digestion. The DNA sequence of selected parts of the inserted DNA is as predicted from the amino acid sequence of prelysozyme. The sequence data allows the unambiguous location of the coding region within lysozyme mRNA.

Animals↗
PubMed1975

[Immunosuppressive treatment of progressive chronic polyarthritis].

After description of forms and possibilities of the immunsuppression the results of this therapy are discussed in 47 own patients with clinically and paraclinically ascertained rheumatoid arthritis. The patients received the sum of 4.0 mg trenimon in combination with altogether 4.0 mg cyclophosphamide by means of 20 infusions with physiological saline solution as carrier substance. Under this treatment in 93.6% of the cases the findings of the examination of joints or the clinical stage improved. As to side effects incompatibilities on the side of the gastro-intestinal tract as well as leucopenias were observed. 18 patients could be after-examined after 6 years. Whilst in every case the clinical stage deteriorated, in the majority the degree of activity remained unchanged. All the results are compared with the results reported in literature. The authors are of the opinion that, when other forms of treatment have no success and contraindication are strongly taken into consideration, the progressing of the rheumatoid arthritis can be retarded by means of immunsuppressives. The pathophysiological processes can, however, scarcely be influenced causally.

Adult↗
PubMedDate not supplied

Deduced amino acid sequence from the bovine oxytocin-neurophysin I precursor cDNA.

The nonapeptide hormone oxytocin-like arginine-vasopressin (AVP) is synthesized as part of a larger precursor polypeptide. The precursor also includes the neurophysin molecule with which the hormone is associated in the neurosecretory granules of the hypothalamo-pituitary tract. A protein of molecular weight (Mr) approximately 20,000 has been isolated from supraoptic nuclei of rat hypothalami which, after tryptic cleavage, released a neurophysin-like molecule of Mr approximately 10,000 and an oligopeptide related to oxytocin. This result was complemented by in vitro translation of bovine hypothalamic mRNA. Among the primary translation products a single polypeptide of Mr approximately 16,500 was shown to contain antigenic determinants recognized by specific antisera against bovine neurophysin I and oxytocin. Here we report the amino acid sequence of the bovine oxytocin-neurophysin I (OT-NpI) precursor which was derived from sequence analysis of the cloned cDNA. As is the case for the bovine arginine-vasopressin-neurophysin II (AVP-NpII) precursor, the signal sequence of the OT-NpI precursor is immediately followed by the nonapeptide hormone which is connected to neurophysin I by a Gly-Lys-Arg sequence. A striking feature of the nucleic acid sequence is the 197-nucleotide long perfect homology with the AVP-NpII precursor mRNA sequence encoding the conserved middle part of neurophysins I and II.

Amino Acid Sequence↗