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S Neuman

Publications and source records attributed to S Neuman.

15 recordsLinked to original sources
PubMed1990

A novel product of the Duchenne muscular dystrophy gene which greatly differs from the known isoforms in its structure and tissue distribution.

A novel transcript of the Duchenne muscular dystrophy gene has been identified. This 6.5 kb mRNA contains sequences from the 3' untranslated region of dystrophin mRNA and from the regions coding for the C-terminal and the cysteine-rich domains. However, probes for the regions encoding the spectrin-like repeats and the actin-binding domain, as well as probes for the first exons of the muscle- and brain-type dystrophin mRNA, did not hybridize with this new mRNA. Significant amounts of the 6.5 kb mRNA were found in a variety of non-muscle tissues, such as liver, testis, lung and kidney, but not in skeletal muscle. The abundance of this mRNA in the brain is at least as high as that of the previously described 14 kb brain-type dystrophin mRNA.

Animals↗
PubMed1989

Duchenne muscular dystrophy gene product is not identical in muscle and brain.

Duchenne muscular dystrophy (DMD) is an X-linked recessive disorder resulting in progressive degeneration of the muscle. It affects about 1 in 3,500 male children. Becker's muscular dystrophy is a less severe disease allelic to DMD. Some 30% of DMD patients suffer from various degrees of mental retardation. The giant DMD gene spans about 2,000 kilobases and codes for a 14-kilobase messenger RNA and a protein of molecular weight 427,000. DMD mRNA is most abundant in skeletal and cardiac muscle and less so in smooth muscle. We reported that the expression of the gene is developmentally regulated during the differentiation of primary muscle cultures and in myogenic cell lines in a way similar to the expression of muscle-specific genes such as myosin light chain 2 and skeletal muscle actin. Similar results have been obtained with human primary myogenic cells. Significant levels of DMD mRNA are found in brain tissue. Here we show that the transcript of the DMD gene and the amino terminal of the encoded protein differ in brain and muscle. The 5' ends of these mRNA species are derived from different exons. The results suggest that the two mRNA types are transcribed from different promoters.

Animals↗
PubMed1985

Highly conserved sequences in the 3' untranslated region of mRNAs coding for homologous proteins in distantly related species.

Comparison of the nucleotide sequence of mRNAs coding for several vertebrate actins revealed a high degree of sequence homology in the 3' untranslated region (3' UTR) between those mRNAs coding for homologous (isotypic) actins in different organisms but not between mRNAs coding for very similar isoforms differing in their function or tissue specificity. A similar pattern of sequence conservation in the 3' UTR is also found in several other genes. Furthermore, while there is a great variation in the size of the 3' UTR of mRNAs coding for different proteins, mRNA coding for isotypic proteins in distantly related organisms often have 3' UTR of similar size. The data suggest that the 3' UTR may play an important role in the regulation of expression of at least some genes at the transcriptional or posttranscriptional level.

Actins↗
PubMed1985

Developmentally regulated expression of a chicken muscle-specific gene in stably transfected rat myogenic cells.

To test the evolutionary conservation of DNA sequences specifying the developmentally regulated expression of the skeletal muscle actin gene, a recombinant plasmid containing the chicken skeletal muscle actin gene was introduced into rat myogenic cells. In a significant number of isolated clones, the accumulation of chicken actin mRNA increased greatly during differentiation. To test the expression in myogenic cells of a gene that is normally expressed during terminal differentiation of another tissue, rat myogenic cells were transfected with a mouse/human beta-globin chimeric gene. A decrease by a factor of 2-3 in the amount of globin mRNA during differentiation was observed in most clones in which the gene was expressed. The results indicate the conservation of the muscle-specific regulatory DNA sequences for more than 300 Myr.

Actins↗
PubMed1984

Eradication of Salmonella and Arizona species from turtle hatchlings produced from eggs treated on commercial turtle farms.

On commercial turtle farms more than 40% of the hatchlings excrete detectable levels of Salmonella and Arizona spp. when hatched from nonsanitized eggs incubated in sawdust or dirt-filled chambers. Over a 3-year period on 10 farms, more than 10(6) turtle eggs were treated in an attempt to hatch Salmonella-free turtles. Eggs were sanitized in disinfectant, treated by temperature- or pressure-differential dip methods in solutions containing 500 micrograms or more of gentamicin sulfate per ml, and hatched in sanitized plastic chambers free of bedding material. The Salmonella and Arizona spp. infection levels for turtles produced from treated eggs were 0 and 1.12% for years 1 and 2, respectively, whereas infection levels for hatchlings produced from nontreated eggs during these periods were 47 and 44%, respectively. During year 3, dip solutions were filtered daily, treated at 100 degrees C for 15 min on a weekly basis to free the solution of microbial contaminants and egg protein, charged with gentamicin after 10,000 to 20,000 eggs had been treated to maintain antimicrobial activity at 500 micrograms/ml or more, and maintained at pH 6.0 to preserve optimal antimicrobial activity. The implementation of these measures in year 3 resulted in an infection level of 0.15% when the tissues of 3 of 1,959 hatchlings tested were positive for Salmonella and Arizona spp., whereas the tissues of 66 (49.0%) of 135 hatchlings produced from nontreated eggs were positive.

Animals↗
PubMed1983

The nucleotide sequence of the rat cytoplasmic beta-actin gene.

The nucleotide sequence of the rat beta-actin gene was determined. The gene codes for a protein identical to the bovine beta-actin. It has a large intron in the 5' untranslated region 6 nucleotides upstream from the initiator ATG, and 4 introns in the coding region at codons specifying amino acids 41/42, 121/122, 267, and 327/328. Unlike the skeletal muscle actin gene and many other actin genes, the beta-actin gene lacks the codon for Cys between the initiator ATG and the codon for the N-terminal amino acid of the mature protein. The usage of synonymous codons in the beta-actin gene is nonrandom, and is similar to that in the rat skeletal muscle and other vertebrate actin genes, but differs from the codon usage in yeast and soybean actin genes.

Actins↗
PubMed1982

Nucleotide sequence of the rat skeletal muscle actin gene.

The actins constitute a family of highly conserved proteins found in all eukaryotic cells. Their conservation through a very wide range of taxonomic groups and the existence of tissue-specific isoforms make the actin genes very interesting for the study of the evolution of genes and their controlling elements. On the basis of amino acid sequence data, at least six different mammalian actins have been identified (skeletal muscle, cardiac muscle, two smooth muscle actins and the cytoplasmic beta- and gamma-actins). Rat spleen DNA digested by the EcoRI restriction enzyme contains at least 12 different fragments with actin-like sequences but only one which hybridized, in very stringent conditions, with the skeletal muscle cloned cDNA probe. Here we describe the sequence of the actin gene in that fragment. The nucleotide sequence codes for two amino acids, Met-Cys, preceding the known N-terminal Asp of the mature protein. There are five small introns in the coding region and a large intron in the 5'-untranslated region. Comparison of the structure of the rat skeletal muscle actin gene with available data on actin genes from other organisms shows that while the sequenced actin genes from Drosophila and yeast have introns at different locations, introns located at codons specifying amino acids 41, 121, 204 and 267 have been preserved at least from the echinoderm to the vertebrates. A similar analysis has been done by Davidson. An intron at codon 150 is common to a plant actin gene and the skeletal muscle acting gene.

Actins↗
PubMed1978

Synthesis of tropomyosin in myogenic cultures and in RNA-directed cell-free systems: qualitative changes in the polypeptides.

The synthesis of polypeptides with the properties of alpha and beta tropomyosin was investigated in differentiating cultures of a myogenic cell line and in a wheat germ cell-free system directed by purified RNA extracted at different stages of differentiation. The polypeptides co-migrate with tropomyosin in isoelectric focusing and SDS two-dimensional gel electrophoresis and SDS-urea/SDS two-dimensional gels. Like authentic tropomyosin, these polypeptides change their mobility greatly in the presence of urea and do not become labeled with proline. The beta tropomyosin synthesized in the intact cells and in the cell-free system can be separated by isoelectric focusing into at least two components. One component (designated beta1) is present in a small amount at all developmental stages examined, and a more basic component (beta2) is specific for differentiated cultures. The synthesis of beta2 in the intact cells and the capacity of purified RNA to direct its synthesis in a cell-free system become detectable and increase greatly during the period of fusion of the mononucleated cells into multinucleated fibers. The results suggest that the beta1 and beta2 tropomyosins are coded for by different genes.

Cell Differentiation↗
PubMed1976

Activity of placental enzymes of carbohydrate and lipid metabolism in normal, toxemic and small-for-date pregnancies.

The specific activity of placental enzymes with a regulatory function in the pathways of glycolysis, gluconeogenesis, NADPH generation and fatty acid synthesis decrease during gestation in the rat. Similar decreases occur in the activity of enzymes of the human placenta when compared between early gestation and term, with the exception of the activity of enzymes related to gluconeogenesis which tend to increase as gestation advances. In term placentas from pregnancies complicated by preeclamptic toxemia, enzyme activities were significantly lower than those in placentas from normal pregnancies, irrespective of whether the baby was of normal weight or small-for-date. This indicates an accelerated decline in placental metabolic function in toxemia. In contrast, in placentas from nontoxemic pregnancies with small-for-date babies the enzyme activities were significantly higher than those in normal term placentas. It is suggested that the decrease in placental enzyme activity, which is associated with placental growth during the course of normal gestation, is retarded in nontoxemic pregnancies with small-for-date babies, apparently due to the arrested aging of the placenta.

Animals↗
PubMed1975

Effect of chorionic gonadotropin, triamcinolone, progesterone and estrogen on enzymes of placenta and liver in rats.

The activity of several enzymes of regulatory importance for the pathways of glycolysis, gluconeogenesis and lipogenesis was investigated in the placenta and liver of pregnant rats and in the liver of non-pregnant female rats. The rats received daily hormonal treatments on Days 15 to 17 of pregnancy and enzyme activities were measured on Day 18. Chorionic gonadotropin induced minor changes in enzyme activity, apart from a decrease in the activity of hepatic enzymes of lipogenesis in non-pregnant rats. Triamcinolone induced a marked increase in enzymes of gluconeogenesis and a decrease in the activity of pyruvate kinase in the liver of pregnant and non-pregnant rats; in contrast, inverse changes in activity, these enzymes were observed in the placenta. This response in the placenta was considered to arise not from direct hormone effect, but from the accompanying hyperglycemia and hyperinsulinemia. Triamcinolone also increased the activity of hepatic acetyl-CoA carboxylase in pregnant and non-pregnant rats, whereas it reduced the activity of this enzyme in the placenta. Estrogen produced changes similar to those of triamcinolone in the liver and placenta, except that it depressed the activity of acetyl-CoA carboxylase in both tissues. Progesterone had little effect on placental and hepatic enzymes. In general, the changes induced by these hormones in the placenta affected fewer enzymes than in the liver, were less extensive in magnitude and not necessarily in the same direction as in the liver. This indicates that the regulatory placental enzymes are subject to specific control mechanisms not necessarily influenced by direct hormone action.

Acetyl-CoA Carboxylase↗