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M Grez

Publications and source records attributed to M Grez.

43 records · Page 3Linked to original sources
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↗
PubMed1980

Exons encode functional and structural units of chicken lysozyme.

The nucleotide sequence was determined for the chicken egg white lysozyme mRNA and for the exons of the gene together with their flanking intron regions. The exon pattern is to some degree related to the structural subdivision of the final protein product. However, the relationship of exons to functional units of the enzyme is better established. Exon 2 codes for amino acids 28-82, which include the catalytically active residues and a cluster of amino acids which bind rings C, D, E, and F of the oligosaccharide substrate. Exon 3 codes for amino acids 82-108, which give additional substrate specificity, determine the cleavage frame for the alternating N-acetylglucosamine/N-acetylmuramic acid chain, and increase the catalytic efficiency of the active center. Exons 1 and 4, respectively, code for translational signal sequences on the mRNA, for the signal peptide of prelysozyme, and for the amino- and carboxy-terminal regions of the enzyme. These regions increase the stability of the molecule but are not directly involved in the catalytic function.

Animals↗
PubMedDate not supplied

Distribution and infection of Langerhans cells in the skin of HIV-infected healthy subjects and AIDS patients.

The in situ content of cells of the reticuloendothelial system and lymphatic cells was examined in the skin of eight symptom-free HIV-positive individuals, three AIDS patients and eleven healthy immunocompetent volunteers. The epidermis was obtained in vivo by the suction blister technique. The numbers of CD68+, CD3+, CD8+, CD25-(IL2R)+ and HLA-DR+ intraepidermal cells proved to be independent of the number of CD4+ peripheral blood lymphocytes. At the same time, the intraepidermal concentrations of these cells were generally low in symptom-free HIV-infected individuals. The strong inverse correlation between the number of epidermal Langerhans cells (LC) and the severity of immunodeficiency was quantitatively confirmed; an increase in LC in symptom-free HIV-infected individuals was found. Thus, the reduction in these cells which was observed in the epidermis of AIDS patients began at a significantly elevated level. In contrast to results from other studies, in AIDS patients, in the present study, the concentration of epidermal LC did not differ significantly from that of healthy immunocompetent volunteers. The immunohistochemical technique can be as effective as in situ hybridization for the detection of HIV in the skin. Our results suggest that the viral load of the skin is rather low in HIV-infected subjects. HIV was demonstrated in one cell of one AIDS case by in situ techniques and this result was confirmed by a polymerase chain reaction examination using the same amount of tissue as for the in situ techniques.(ABSTRACT TRUNCATED AT 250 WORDS)

Acquired Immunodeficiency Syndrome↗
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↗