Search PubMed⌕ Search

Biomedical subjects

M Carlson

Publications and source records attributed to M Carlson.

At least 145 records · Page 8Linked to original sources
PubMed1991

Identification and characterization of the familial adenomatous polyposis coli gene.

DNA from 61 unrelated patients with adenomatous polyposis coli (APC) was examined for mutations in three genes (DP1, SRP19, and DP2.5) located within a 100 kb region deleted in two of the patients. The intron-exon boundary sequences were defined for each of these genes, and single-strand conformation polymorphism analysis of exons from DP2.5 identified four mutations specific to APC patients. Each of two aberrant alleles contained a base substitution changing an amino acid to a stop codon in the predicted peptide; the other mutations were small deletions leading to frameshifts. Analysis of DNA from parents of one of these patients showed that his 2 bp deletion is a new mutation; furthermore, the mutation was transmitted to two of his children. These data have established that DP2.5 is the APC gene.

Adenomatous Polyposis Coli↗
PubMed1991

Identification of deletion mutations and three new genes at the familial polyposis locus.

Small (100-260 kb), nested deletions were characterized in DNA from two unrelated patients with familial adenomatous polyposis coli (APC). Three candidate genes located within the deleted region were ascertained and a previous candidate gene, MCC, was shown to be located outside the deleted region. One of the new genes contained sequence identical to SRP19, the gene coding for the 19 kd component of the ribosomal signal recognition particle. The second, provisionally designated DP1 (deleted in polyposis 1), was found to be transcribed in the same orientation as MCC. Two other cDNAs, DP2 and DP3, were found to overlap, forming a single gene, DP2.5, that is transcribed in the same orientation as SRP19.

Adenomatous Polyposis Coli↗
PubMed1991

Functional interdependence of the yeast SNF2, SNF5, and SNF6 proteins in transcriptional activation.

The SNF2, SNF5, and SNF6 genes of Saccharomyces cerevisiae are required for expression of a variety of differently regulated genes. Previous evidence implicated the SNF5 protein in transcriptional activation, and a DNA-bound LexA-SNF5 fusion protein was shown to activate expression of a nearby promoter. Here, we examine the functional relationship of the SNF2, SNF5, and SNF6 proteins. Activation by DNA-bound LexA-SNF5 fusion protein was greatly reduced in snf2 and snf6 mutants, indicating that activation by LexA-SNF5 requires SNF2 and SNF6 function. An spt6 mutation, which suppresses transcriptional defects caused by snf2, restored activation by LexA-SNF5 in a snf2 mutant. The SNF2 gene was sequenced and encodes a 194-kDa protein that is targeted to the nucleus. DNA-bound LexA-SNF2 fusion protein also activated transcription, dependent on SNF5 and SNF6. These findings suggest that SNF2, SNF5, and SNF6 function interdependently in transcriptional activation, possibly forming a heteromeric complex.

Adenosine Triphosphatases↗
PubMed1991

Nitrate-nitrite levels in commercially processed and home processed beets and spinach.

Nitrate and nitrite content of commercially processed and home processed beets and spinach samples were analyzed using specific ion electrode and colorimetric methods. The home processed beets were found to be significantly higher in nitrate content than the commercially processed beets. This difference was attributed to differences in processing methods. Pickled and Harvard beets contained significantly lower amounts of nitrate/nitrite on a dry weight basis than the other types of processed beets, evidently due to the diluting effect of added sucrose. Home frozen spinach showed a trend toward lower nitrate content than commercially frozen spinach, although the difference was not significant. Length of storage of home processed beets and spinach did not appear to affect nitrate or nitrite content.

Colorimetry↗
PubMed1991

Secretion of granule proteins from eosinophils and neutrophils is increased in asthma.

The activity of eosinophil and neutrophil granulocytes with respect to secretion of granule proteins was studied in 30 patients with asthma and with varying severity of their disease. Granulocytes were stimulated with serum-opsonized Sephadex particles, and the released amount of eosinophil cationic protein (ECP), eosinophil protein X (EPX), and myeloperoxidase was measured by means of specific radioimmunoassays. Eosinophils from patients with asthma released significantly more (p less than 0.001) ECP and EPX after 20 minutes of incubation than cells from control subjects without asthma. The release of myeloperoxidase from neutrophils was also somewhat higher (p less than 0.03). The serum concentrations of ECP and EPX were also significantly increased (p less than 0.001) in the group with asthma. No significant relationships were found between clinical variables and the secretory activity of either eosinophils or neutrophils. We conclude that eosinophils and, to some extent, neutrophils from subjects with asthma have an increased propensity to release their granule proteins, which we suggest is a consequence of priming of these cells.

Adult↗
PubMed1991

Dominant and recessive suppressors that restore glucose transport in a yeast snf3 mutant.

The SNF3 gene of Saccharomyces cerevisiae encodes a high-affinity glucose transporter that is homologous to mammalian glucose transporters. To identify genes that are functionally related to SNF3, we selected for suppressors that remedy the growth defect of snf3 mutants on low concentrations of glucose or fructose. We recovered 38 recessive mutations that fall into a single complementation group, designated rgt1 (restores glucose transport). The rgt1 mutations suppress a snf3 null mutation and are not linked to snf3. A naturally occurring rgt1 allele was identified in a laboratory strain. We also selected five dominant suppressors. At least two are tightly linked to one another and are designated RGT2. The RGT2 locus was mapped 38 cM from SNF3 on chromosome IV. Kinetic analysis of glucose uptake showed that the rgt1 and RGT2 suppressors restore glucose-repressible high-affinity glucose transport in a snf3 mutant. These mutations identify genes that may regulate or encode additional glucose transport proteins.

DNA Mutational Analysis↗
PubMed1991

New SNF genes, GAL11 and GRR1 affect SUC2 expression in Saccharomyces cerevisiae.

To identify new genes required for depression of the SUC2 (invertase) gene in Saccharomyces cerevisiae, we have isolated mutants with defects in raffinose utilization. In addition to mutations in SUC2 and previously identified SNF genes, we recovered recessive mutations that define four new complementation groups, designated snf7 through snf10. These mutations cause defects in the derepression of SUC2 in response to glucose limitation. We also recovered five alleles of gal11 and showed that a gal11 null mutation decreases SUC2 expression to 30% of the wild-type level. Finally, one of the mutants carries a grr1 allele that converts SUC2 from a glucose-inducible gene.

Alleles↗
PubMed1991

Effect of dietary calcium on bone density in growing rabbits.

Reductions in peak bone mass at skeletal maturity may increase the risk for the subsequent development of osteoporosis. Although changes in calcium intake can modify the rate of decline in bone density in the mature skeleton, longitudinal assessments of the effect of dietary calcium supplementation during skeletal growth on peak bone mass have not been done in humans or experimental animals. Thus quantitative computed tomography (QCT) was used to monitor changes in vertebral bone density at 6-wk intervals during growth from 8 wk of age until skeletal maturity at 35 wk in male New Zealand White rabbits maintained on diets containing 0.15% (low Ca), 0.45% (normal Ca), or 1.35% (high Ca) calcium. Serum parathyroid hormone (PTH) and calcitriol levels increased, and renal calcium excretion decreased in low Ca compared with normal Ca; in contrast, serum calcitriol levels decreased and renal calcium excretion increased from control values in high Ca. Vertebral bone density by QCT did not differ during growth between high Ca and normal Ca, and peak values at epiphyseal closure also did not differ in these two groups. Vertebral bone density was lower, however, throughout the study in low Ca, and peak values at epiphyseal closure remained below those in either normal Ca or high Ca. Quantitative bone histology revealed decreases in cortical thickness in the third lumbar vertebra in low Ca, whereas trabecular bone area did not differ among groups; there was no histological evidence of osteomalacia in low Ca. Thus dietary calcium restriction during growth reduces peak bone mass at skeletal maturity, but raising dietary calcium intake above normal levels does not increase peak bone mass in this experimental model.

Animals↗
PubMed1990

Increased dosage of the MSN1 gene restores invertase expression in yeast mutants defective in the SNF1 protein kinase.

The SNF1 protein kinase is required for expression of the invertase gene in response to glucose deprivation in Saccharomyces cerevisiae. We selected for genes that in multicopy suppress the invertase defect of temperature-sensitive snf1 mutants. Increased dosage of the MSN1 gene restores high-level, regulated invertase expression in snf1-ts mutants, and disruption of MSN1 in the wild type reduces invertase expression a fewfold. MSN1 gene dosage does not affect SNF1 protein kinase activity in vitro. MSN1 encodes a 43-kilodalton protein, and a MSN1-beta-galactosidase fusion protein was localized in the nucleus. A LexA-MSN1 fusion protein, when bound to a lexA operator, activates transcription of an adjacent promoter. In vitro synthesized MSN1 protein exhibits weak, nonspecific DNA-binding activity.

Amino Acid Sequence↗
PubMed1990

Migratory responses of eosinophil and neutrophil granulocytes from patients with asthma.

In the present study the migratory function of eosinophil and neutrophil granulocytes from patients with asthma were investigated. Fifty-seven patients with asthmatic disease of varying severity were included. Eosinophil and neutrophil chemotactic responses to 5% pooled normal human serum (NHS), 5% allergen-challenge serum, 2.5% zymosan-activated serum, N-formyl-methionyl-leucyl-phenylalanine (10 nmol/L), chemokinetic responses to albumin (2 gm/L) and 5% NHS, and the eosinophil and neutrophil chemotactic and chemokinetic activities of serum were investigated. Eosinophils from patients with asthma demonstrated significantly (p less than 0.02) increased chemotactic responses to allergen-challenge serum, zymosan-activated serum, and N-formyl-methionyl-leucyl-phenylalanine, compared with eosinophils from references. The chemokinetic responses to albumin and NHS were increased (p less than 0.01) by eosinophils from the patients who had blood eosinophilia (greater than 400 X 10(6)/L). Sera from the patients with asthma demonstrated raised eosinophil chemotactic activity (p less than 0.001) and raised eosinophil and neutrophil chemokinetic activity (p less than 0.001). The eosinophil chemokinetic activity of serum was correlated to the relative peak expiratory flow rate of the patients (r = -0.43; p less than 0.02). The increased migratory responses were specific for the eosinophils, since the migratory responses of their neutrophils were not altered compared with that of the references. These results suggest that the eosinophils from the patients with asthma had been exposed to a priming mechanism in vivo.

Adolescent↗
PubMed1990

Effects of situational aggression cues: a quantitative review.

Meta-analytic procedures were used to assess the degree to which aggression-related cues present in the environment facilitate aggressive responding among negatively aroused subjects. The first study, which examined the so-called weapons effect, the effect of name-mediated cues, and other cue effects, showed clear evidence that aggression cues augment aggressive responses in negatively aroused subjects. This was true for the overall analysis and for name-mediated cues, but confirmation of the weapons effect was restricted to cases wherein subject sophistication and evaluation apprehension were low. A second study used partial correlation analysis to assess independently the effects of seven potential mediators of aggression cue effects. Of these, target-based facilitation and harm capacity of the aggressive response were found to mediate the magnitude of cue-facilitated aggression. A third study showed that these mediators augmented cue effects among neutral as well as negatively aroused subjects. These outcomes are interpreted as emphasizing the role of cognitive factors in the expression of both impulsive and nonimpulsive aggression.

Affect↗
PubMed1990

The SNF5 protein of Saccharomyces cerevisiae is a glutamine- and proline-rich transcriptional activator that affects expression of a broad spectrum of genes.

The Saccharomyces cerevisiae SNF5 gene affects expression of both glucose- and phosphate-regulated genes and appears to function in transcription. We report the nucleotide sequence, which predicts that SNF5 encodes a 102,536-dalton protein. The N-terminal third of the protein is extremely rich in glutamine and proline. Mutants carrying a deletion of the coding sequence were viable but grew slowly, indicating that the SNF5 gene is important but not essential. Evidence that SNF5 affects expression of the cell type-specific genes MF alpha 1 and BAR1 at the RNA level extends the known range of SNF5 function. SNF5 is apparently required for expression of a wide variety of differently regulated genes. A bifunctional SNF5-beta-galactosidase fusion protein was localized in the nucleus by immunofluorescence. No DNA-binding activity was detected for SNF5. A LexA-SNF5 fusion protein, when bound to a lexA operator, functioned as a transcriptional activator.

Amino Acid Sequence↗
PubMed1990

Mutational analysis of the SNF3 glucose transporter of Saccharomyces cerevisiae.

The SNF3 gene of Saccharomyces cerevisiae encodes a high-affinity glucose transporter that is homologous to mammalian glucose transporters. Point mutations affecting the function of the transporter were recovered from the genomes of four snf3 mutants and characterized. Two of the mutations introduced a charged amino acid into the first and second predicted membrane-spanning regions, respectively. The analogs of a bifunctional SNF3-lacZ fusion containing these two mutations were constructed, and the mutant fusion proteins were not localized to the plasma membrane, as judged by immunofluorescence microscopy. The third mutation produced a valine-to-isoleucine substitution in hydrophobic region 8, and the corresponding mutant fusion protein was correctly localized. The finding that this conservative change causes a transport defect is consistent with the possibility that this transmembrane region, which could exist as an amphipathic alpha-helix, forms part of the glucose channel through the membrane. The fourth snf3 allele harbored an ochre mutation midway through the coding sequence. We have also constructed mutations in the cloned SNF3 gene. A major difference between the yeast SNF3 protein and mammalian glucose transporters is the presence in the SNF3 protein of an additional 303 amino acids at the C terminus. Analysis of a series of C-terminal deletions and fusions to lacZ showed that this C-terminal region is important, but not essential, for transport function. We also report the genetic mapping of the SNF3 locus on the left arm of chromosome IV.

Base Sequence↗
PubMed1990

SNF6 encodes a nuclear protein that is required for expression of many genes in Saccharomyces cerevisiae.

The SNF6 gene appears to affect transcription from a variety of promoters in Saccharomyces cerevisiae. The gene was cloned, and sequence analysis revealed two completely overlapping open reading frames of 996 and 1092 nucleotides on opposite strands. The SNF6 coding sequence was identified by selective mutagenesis. The predicted 37,604-dalton SNF6 protein is highly charged but overall neutral. A bifunctional SNF6-beta-galactosidase fusion protein was localized in the nucleus, as judged by immunofluorescence microscopy. The N terminus of SNF6 contains a sequence homologous to nuclear localization signals and was sufficient to direct beta-galactosidase to the nucleus. The 5' ends of the SNF6 RNA were heterogeneous and included ends mapping downstream from the first ATG codon. Construction of a frameshift mutation provided evidence that translational initiation at the second ATG yields a partially functional SNF6 product. Null mutations in SNF6 caused a wider range of pleiotropic defects than the previously isolated point mutation, including slow growth. Genetic and molecular evidence suggested that SNF6 is functionally related to the SNF2 and SNF5 genes. These genes may function together to affect transcription.

Alleles↗
PubMed1990

The N-terminal TPR region is the functional domain of SSN6, a nuclear phosphoprotein of Saccharomyces cerevisiae.

The SSN6 protein functions as a negative regulator of a variety of genes in Saccharomyces cerevisiae and is required for normal growth, mating, and sporulation. It is a member of a family defined by a repeated amino acid sequence, the TPR (tetratricopeptide repeat) motif. Here, we have used specific antibody to identify and characterize the SSN6 protein. Both SSN6 and a bifunctional SSN6-beta-galactosidase fusion protein were localized in the nucleus by immunofluorescence staining. The N-terminal one-third of the protein containing the TPR units was identified as the region that is important for SSN6 function. Analysis of four nonsense alleles, isolated as intragenic suppressors of an ssn6::URA3 insertion, revealed that polypeptides truncated after TPR unit 7 provide SSN6 function. Deletion analysis suggested that TPR units are required but that 4 of the 10 TPR units are sufficient. In addition, deletion studies indicated that three very long, homogeneous tracts of polyglutamine and poly(glutamine-alanine) are dispensable. Previous genetic evidence suggested the SSN6 protein as a possible target of the SNF1 protein kinase. Here, we show that the C terminus of SSN6 is phosphorylated in vivo and that the SNF1 kinase is not responsible for most of the phosphorylation. Finally, SSN6 has a modest effect on the maintenance of minichromosomes.

Alleles↗
PubMed1990

SPT6, an essential gene that affects transcription in Saccharomyces cerevisiae, encodes a nuclear protein with an extremely acidic amino terminus.

SPT6 is an essential gene of Saccharomyces cerevisiae that appears to play a role in transcription. Mutations in the SPT6 (SSN20, CRE2) gene suppress delta insertion mutations in the 5' regions of HIS4 and LYS2 and mutations in cis- and/or trans-acting elements that are required for expression of SUC2 and ADH2. We report here that SPT6 encodes a 170-kilodalton highly charged protein with an extremely acidic amino terminus. By use of an epitope-tagged SPT6 protein, we have determined by indirect immunofluorescence that the SPT6 protein is located in the nucleus.

Amino Acid Sequence↗