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Biomedical subjects

M A Kay

Publications and source records attributed to M A Kay.

105 records · Page 6Linked to original sources
PubMed1992

Hepatic gene therapy: persistent expression of human alpha 1-antitrypsin in mice after direct gene delivery in vivo.

The liver represents an excellent target organ for gene therapy. The current strategy for hepatic gene therapy involves the isolation of primary hepatocytes from a resected liver lobe, transduction of therapeutic genes in vitro followed by autologous hepatocellular transplantation. This ex vivo approach is a rather complex procedure in its entirety; thus, a simple method for direct gene delivery into hepatocytes in vivo has been developed. The procedure involves partial hepatectomy followed by the portal vein infusion of recombinant retroviral vectors. Histological analysis of hepatocytes after in vivo delivery of a recombinant retrovirus bearing the E. coli beta-galactosidase gene showed that 1-2% of the parenchymal cells were transduced. Direct hepatic transfer of human alpha 1-antitrypsin cDNA under the transcriptional direction of the albumin promoter-enhancer led to constitutive expression of the human protein in the sera of recipients at concentrations of 30-1,400 ng/ml for at least 6 months. The experimental animals showed no signs of illness and histologic analysis of the liver revealed no evidence of pathologic abnormalities. The results suggest that the in vivo approach is an attractive alternative for hepatic gene therapy.

Albumins↗
PubMed1988

Identification and germline transformation of the ribosomal protein rp21 gene of Drosophila: complementation analysis with the Minute QIII locus reveals nonidentity.

Minute loci represent a class of about 50 different Drosophila genes that appear to be functionally related. These genes may code for components of the protein synthetic apparatus. While one Minute locus has been recently shown to code for a ribosomal protein, it is not yet known whether any of the other Minute loci also code for ribosomal proteins. We have addressed this question by a combined molecular and genetic approach. In this report, a cloned DNA encoding the ribosomal protein rp21 is partially characterized. The rp21 gene maps to the same region (region 80 of chromosome 3L) as the temperature-sensitive Minute QIII gene. Using P-element mediated transformation, the rp21 gene was transformed into the germline of Drosophila. RNA blot experiments revealed that the transformed gene is expressed in transgenic flies. However, genetic complementation analysis indicated that the QIII locus and the rp21 gene are not identical. Implications of these findings for the relationship between Minutes and ribosomal protein genes are discussed.

Animals↗
PubMed1987

Structural analysis of the Drosophila rpA1 gene, a member of the eucaryotic 'A' type ribosomal protein family.

The expression of ribosomal protein (r-protein) genes is uniquely regulated at the translational level during early development of Drosophila. Here we report results of a detailed analysis of the r-protein rpA1 gene. A cloned DNA sequence coding for rpA1 has been identified by hybrid-selected translation and amino acid composition analysis. The rpA1 gene was localized to polytene chromosome band 53CD. The nucleotide sequence of the rpA1 gene and its cDNA have been determined. rpA1 is a single copy gene and sequence comparison between the gene and its cDNA indicates that this r-protein gene is intronless. Allelic restriction site polymorphisms outside of the gene were observed, while the coding sequence is well conserved between two Drosophila strains. The protein has unusual domains rich in Ala and charged residues. The rpA1 is homologous to the "A" family of eucaryotic acidic r-proteins which are known to play a key role in the initiation and elongation steps of protein synthesis.

Amino Acid Sequence↗
PubMed1985

Selective translational regulation of ribosomal protein gene expression during early development of Drosophila melanogaster.

We have previously characterized a cloned cDNA coding for a developmentally regulated mRNA in Drosophila melanogaster whose expression is selectively regulated at the translational level during oogenesis and embryogenesis. In this report we show that this translationally regulated mRNA (rpA1) codes for an acidic ribosomal protein. Furthermore, our results indicate that most ribosomal protein mRNAs are regulated similarly to rpA1 mRNA. This conclusion is based on cell-free translation of mRNAs derived from polysomes and postpolysomal supernatants as well as in vivo labeling experiments. Thus, the translation of many ribosomal protein mRNAs appears to be temporally related to the synthesis of rRNA during D. melanogaster development. The relationship between rRNA transcription and ribosomal protein mRNA translation was further investigated by genetically reducing rRNA synthesis with the use of bobbed mutants. Unexpectedly, neither ribosomal protein mRNA abundance nor translation was altered in these mutants.

Animals↗
PubMed1985

Changing patterns of femoral and skeletal mineralization during growth in juvenile X-linked hypophosphatemic mice.

Femoral and skeletal mineralization were studied in normal and X-linked hypophosphatemic (Hyp) mice from birth to 13 weeks of age. Although the Hyp mice were continuously hypophosphatemic, their body weight, trunk length, femoral ash weight and total body calcium content were not significantly affected through 3 weeks of age. Tail length and femoral length were depressed by less than 10%. Between 3 and 7 weeks of age the normal mice continued their rapid growth, but there was little further lengthening of the femur or tail in the Hyp mice; body weight and trunk length fell behind the normals; and there was no further accumulation of femoral ash weight or total body calcium and little increase in total body phosphate. After 7 weeks of age the Hyp mice resumed accumulation of femoral and total body mineral.

Aging↗
PubMedDate not supplied

Liver-associated toxicity of the HSV-tk/GCV approach and adenoviral vectors.

Intravenous injection of immunodeficient mice with adenoviral vectors carrying the HSV-tk gene led to preferential transduction of liver tissue. Subsequent application of ganciclovir (GCV) resulted in extremely high toxicity with negligible survival rates. This toxicity was only seen when GCV was applied in addition to the adenoviral vector and not if combined with the Ad-beta gal control vector. This indicates a specific Ad-tk/GCV-related toxicity. Low survival rates were seen not only after intravenous administration but also after injection of the vectors into the portal vein, the liver tissue and liver tumors, but not during the treatment of subcutaneous tumors. This, together with extensive signs of liver degeneration occurring as early as one day after the initiation of GCV treatment, strongly suggests a specific liver-associated toxicity. Severe toxicity was observed when animals received GCV treatment as late as 7 weeks after vector administration. Moreover, in vitro survival rates of resting primary hepatocytes treated with Ad-tk and GCV were very low. We therefore suppose a mechanism of toxicity of phosphorylated GCV which is independent from cellular proliferation. Since our results indicate that the Ad-HSV-tk/GCV approach is toxic for the resting liver, additional safety features such as tumor-restricted transgene expression should be included in adenoviral vectors.

Adenoviridae↗