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G Whitney

Publications and source records attributed to G Whitney.

At least 19 recordsLinked to original sources
PubMed2001

A new siglec family member, siglec-10, is expressed in cells of the immune system and has signaling properties similar to CD33.

The siglecs (sialic acid-binding Ig-like lectins) are a distinct subset of the Ig superfamily with adhesion-molecule-like structure. We describe here a novel member of the siglec protein family that shares a similar structure including five Ig-like domains, a transmembrane domain, and a cytoplasmic tail containing two ITIM-signaling motifs. Siglec-10 was identified through database mining of an asthmatic eosinophil EST library. Using the Stanford G3 radiation hybrid panel we were able to localize the genomic sequence of siglec-10 within the cluster of genes on chromosome 19q13.3-4 that encode other siglec family members. We have demonstrated that siglec-10 is an immune system-restricted membrane-bound protein that is highly expressed in peripheral blood leukocytes as demonstrated by Northern, RT-PCR and flow cytometry. Binding assays determined that the extracellular domain of siglec-10 was capable of binding to peripheral blood leukocytes. The cytoplasmic tail of siglec-10 contains four tyrosines, two of which are embedded in ITIM-signaling motifs (Y597 and Y667) and are likely involved in intracellular signaling. The ability of tyrosine kinases to phosphorylate the cytoplasmic tyrosines was evaluated by kinase assay using wild-type siglec-10 cytoplasmic domain and Y-->F mutants. The majority of the phosphorylation could be attributed to Y597 andY667. Further experiments with cell extracts suggest that SHP-1 interacts with Y667 and SHP-2 interacts with Y667 in addition to another tyrosine. This is very similar to CD33, which also binds the phosphatases SHP-1 and SHP-2, therefore siglec-10, as CD33, may be characterized as an inhibitory receptor.

Amino Acid Motifs↗
PubMed2000

Sucrose octaacetate avoidance in nontaster mice is not enhanced by two type-A Prp transgenes from taster mice.

The Soa bitter-sensitivity and Prp salivary-protein loci map to distal mouse chromosome six. No recombination has been found between sucrose octaacetate (SOA)-avoidance phenotype and PRP haplotype in any mouse population. Soa and Prp, therefore, are either very near each other or identical. To assess the latter possibility, two type-A, proline-rich protein genes (MP2 and M14), situated approximately 30 kb apart at the Prp locus, were separately transferred from an SOA-taster inbred strain (SWR) to an SOA-nontaster inbred strain (FVB). Five MP2-transgenic mice and seven M14-transgenic mice were insensitive to 1 mM SOA in two-bottle tests, thus retaining the nontaster FVB phenotype. Each transgenic mouse was mated to control FVB mice. Their transgene-positive F1 and F2 offspring also were insensitive. Transgene expression varied among the founder lines, but SWR-like expression levels, higher than background FVB expression levels, were found in submandibular gland tissue of adult transgenic mice from two MP2 lines and one M14 line. F3 mice from one of these MP2 lines were mated to F2 mice from the M14 line. Nine offspring inherited both transgenes. All nine were insensitive to 1 mM SOA. These findings indicated that expression of mRNAs for both type-A Prp genes alone or together did not enhance SOA taste sensitivity in nontaster mice.

Animals↗
PubMed2000

Reply to Winston and Peters' "On the presentation and interpretation of international homicide data...".

The rationale not previously given for handling a data entry for the USA in a prior paper is carefully described, which makes clear the criticism leveled is not appropriate. Further, brief murder data were presented to illustrate "Brimelow's theory of emotional conditioning," which suggests a strong taboo against consideration of any genetic contribution to differences among races.

Cause of Death↗
PubMed1998

A common polygenic basis for quinine and PROP avoidance in mice.

Inbred strains of mice (Mus musculus) differ greatly in ability to taste various bitter compounds. For some compounds, the differences result from allelic variation at a single locus. However, segregation patterns incompatible with monogenic inheritance have been found for quinine avoidance. The Soa bitter sensitivity locus exerts some influence on this phenotype, but an unknown number of other loci also contribute. Relative avoidance patterns for quinine sulfate in panels of naive inbred strains resembled avoidance patterns for 6-n-propyl-2-thiouracil (PROP), suggesting a common genetic basis. In particular, C57BL/6J mice strongly avoided both 0.1 mM quinine sulfate and 1 mM PROP in two-bottle preference tests, whereas C3H/HeJ mice were indifferent to both. Therefore, 12 BXH/Ty recombinant inbred strains, derived from these strains, were tested with both solutions to begin identification of the unknown bitter loci. Naive mice were tested for four consecutive days with each compound (order counterbalanced). Some BXH/Ty strain means resembled those of the parent strains, but others were intermediate. This indicated recombination among loci affecting avoidance, and therefore polygenic inheritance. The strain means were highly correlated across compounds (r = 0.98), suggesting that the same polygenes controlled both phenotypes. The BXH/Ty means for both compounds were then compared with the strain genotypes at 212 chromosome position markers distributed throughout the genome. Eight markers on five chromosomes (3, 6, 7, 8 and 9) yielded significant correlations. Six of the markers were correlated with both phenotypes, again suggesting common polygenic inheritance. The marker with the highest correlation was Prp, tightly linked to Soa on chromosome 6. The correlated marker regions likely contain quantitative trait loci affecting bitter avoidance. The phenotypic similarity of PROP to quinine, rather than to phenylthiourea, apparently stemming from a common polygenic basis, indicates a difference between mice and humans in gustatory organization related to bitters.

Alleles↗
PubMed1997

Behavioral specificity of the bitter taste gene Soa.

In mice, aversion to the bitter acetylated sugar sucrose octaacetate (SOA) is determined by a single genetic locus with three alleles. SWR/J (SW) inbred mice are SOA tasters: They avoid many compounds characterized as bitter-tasting by humans, at concentrations to which C3HeB/FeJ (C3:SOA demitasters) mice are less sensitive. C3.SW-Soa(a) congenic taster mice contain the taster allele transposed to a 99% C3 bitter-insensitive genetic background. SW, C3, C3.SW-Soa(a) congenic taster, and C3.SW demitaster mice were behaviorally tested with a series of 48-h two-bottle preference tests to determine the influence of the Soa(a) taster allele on sensitivity to a variety of bitter-tasting compounds. Soa allelic variation had a major effect on sensitivity to 0.003-1.0 mM SOA and several concentrations of the bitter-tasting alkaloids brucine, strychnine, and quinine. Effects were also found for 0.1 mM denatonium and 1 mM propylthiouracil. For caffeine, cycloheximide, thiamine, and two nonbitter compounds (NaCl and calcium hydroxide), the SW mice avoided lower concentrations than the other strains, but this avoidance was not due to the Soa(a) allele because both the C3 inbred and C3.SW-Soa(a) congenics were less sensitive. These results suggest the Soa gene product influences sensitivity to a subset of bitter-tasting compounds.

Alleles↗
PubMed1996

SW.B6-Soa(b) nontaster congenic strains completed and a sucrose octaacetate congenic quartet tested with other bitters.

Ten SW.B6 SOA nontaster strains congenic with the SWR/J SOA taster inbred strain were bred via repeated backcross-intercross cycles, with selection for nontasting in each cycle. Preference ratio distributions and phenotypic proportions across cycles at 0.1 mM SOA were consistent with monogenic predictions. The SW.B6 mice completed a congenic quartet with the SWR/J, B6.SW SOA taster and C57BL/6J SOA nontaster strains. The Soa locus controlled avoidance differences within the quartet for SOA, raffinose undecaacetate, glucose pentaacetate and brucine. Background genes not linked to Soa controlled avoidance differences for L-phenylalanine and ethanol. Avoidance of bitter picric acid was influenced by the Soa locus, but avoidance of acetic acid was not. The quartet pattern for quinine HCl was unclear, with indications of both Soa and background effects. Two forms of ribose tetraacetate yielded different patterns. Avoidance differences controlled by the Soa locus were found for the pyranose form; however, all four strains avoided the furanose form. The pleiotropic effects of Soa allele substitution within the quartet were limited to a subset of bitter compounds.

Acids↗
PubMed1996

Rapid kinetics of second messenger production in bitter taste.

The tasting of bitter compounds may have evolved as a protective mechanism against ingestion of potentially harmful substances. We have identified second messengers involved in bitter taste and show here for the first time that they are rapid and transient. Using a quench-flow system, we have studied bitter taste signal transduction in a pair of mouse strains that differ in their ability to taste the bitter stimulus sucrose octaacetate (SOA); however, both strains taste the bitter agent denatonium. In both strains of mice, denatonium (10 mM) induced a transient and rapid increase in levels of the second messenger inositol 1,4,5-trisphosphate (IP3) with a maximal production near 75-100 ms after stimulation. In contrast, SOA (100 microM) brought about a similar increase in IP3 only in SOA-taster mice. The response to SOA was potentiated in the presence of GTP (1 microM). The GTP-enhanced SOA-response supports a G protein-mediated response for this bitter compound. The rapid kinetics, transient nature, and specificity of the bitter taste stimulus-induced IP3 formation are consistent with the role of IP3 as a second messenger in the chemoelectrical transduction of bitter taste.

Animals↗
PubMed1995

C3.SW-Soaa heterozygous congenic taster mice.

Sensitivity to the bitter acetylated sugar sucrose octaacetate (SOA) is mediated by a single-locus system with three alleles in mice. Inbred strains are classified according to SOA phenotype as tasters, nontasters, or demitasters (intermediate sensitivity). A congenic quartet created from taster and nontaster strains has been used to investigate the effect of the Soa locus on non-SOA aspects of taste sensitivity. In this study, we created a third congenic set, C3.SW-Soaa, from taster (SWR/J) and demitaster (C3HeB/FeJ) strains. After 11 lineal backcross generations these C3.SW mice carry the tasting allele on a 99% C3 demitaster background. After testing a total of 938 mice, taster-demitaster proportions across 12 generations were consistent with expectations from a monogenic model. The resultant three-strain congenic series will allow further examination of the mechanisms of taste.

Alleles↗
PubMed1995

Cloning and characterization of murine CD6.

The lymphocyte antigen CD6 has been extensively studied in humans, but has not been reported in mouse. Here we describe the isolation and characterization of a cDNA clone encoding the murine homologue of the human lymphocyte antigen CD6. Comparison of the predicted amino acid sequence of human and murine CD6 shows that the cytoplasmic domain of murine CD6 is 160 residues longer than that of the human protein. Inspection of the 3' untranslated sequence of the human CD6 clone and the genomic organization of the murine CD6 gene suggests the expression of differentially spliced CD6 polypeptides in both species.

Amino Acid Sequence↗
PubMed1995

Kinase activation and smooth muscle contraction in the presence and absence of calcium.

PURPOSE: The intracellular signalling mechanisms that modulate the sustained vascular smooth muscle contractions that occur with vasospasm are not well understood. The purpose of this investigation was to examine cell signalling mechanisms that account for sustained vascular smooth muscle contraction, independent of increases in intracellular Ca2+ concentrations ([Ca2+]i). METHODS: Fresh bovine carotid artery smooth muscles contractile responses were examined in a muscle bath. [Ca2+]i was depleted by use of the extracellular Ca2+ chelator, ethylene glycol-bis(beta-aminoethylether) N,N,N',N'-tetraacetic acid and the intracellular chelator, 1,2-bis(2-aminophenoxy)ethane-N,N,N',N',-tetraacetic acid. RESULTS: In Ca(2+)-free conditions, depolarizing the membrane with high extracellular KCI failed to elicit a contraction. In addition, in Ca(2+)-free conditions the ([Ca2+]i) was less than 10 nmol/L as determined with the Ca(2+)-indicator, Fura 2. The protein kinase C (PKC) activator, phorbol 12, 13-dibutyrate (PDBu), induced slowly developing sustained contractions in bovine carotid artery smooth muscle, and the magnitude of the contractile response to PDBu (10 nmol/L to 10 mumol/L) was the same in the presence and absence of Ca2+. PDBu induced contractions in Ca(2+)-free conditions were not inhibited by the myosin light chain kinase inhibitor, ML-9 (50 mumol/L), but were inhibited by the PKC inhibitor, staurosporine (50 nmol/L). CONCLUSIONS: These data suggest that vascular smooth muscle contractions can occur under conditions where the [Ca2+]i is low and fixed and that these contractions may be mediated by PKC.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1995

The genetic basis of preference for sweet substances among inbred strains of mice: preference ratio phenotypes and the alleles of the Sac and dpa loci.

Five inbred strains (129/J, BALB/cByJ, C3HeB/FeJ, C57BI/6J and DBA/2J) were examined with two-bottle (48 h) preference ratio testing across concentrations of sodium saccharin (3 x 10(-4) M, 10(-3) M, 3 x 10(-3) M and 10(-2) M), d-phenylalanine (10(-3) M, 10(-2) M and 10(-1) M), and l-glutamine (10(-2) M, 3 x 10(-2) M, 10(-1) M and 3 x 10(-1) M). Three consistent groupings of strains were observed across substances and concentrations: (1) C57BI/6J (preference at low and high concentrations); (2) BALB/cByJ and C3HeB/FeJ (preference at high concentrations); (3) 129/J and DBA/2J (preference at high concentration for sodium saccharin and indifference to d-phenylalanine and l-glutamine). If a single locus (presumably dpa or Sac) determines these phenotypes, there are likely to be three alleles. If two independent loci (presumably dpa and Sac) determine these phenotypes, an allelic assignment of Sacb/dpa+s for the C57BI/6J strain, Sacb/dpa-s for the BALB/cByJ and C3HeB/FeJ strains, and either Sacd/dpa+s or Sacd/dpa-s for the 129/J and DBA/2J strains is suggested.

Alleles↗
PubMed1994

A transmembrane-anchored chimeric focal adhesion kinase is constitutively activated and phosphorylated at tyrosine residues identical to pp125FAK.

Focal adhesion kinase, pp125FAK, is a nonmyristylated cytosolic tyrosine kinase unrelated to protein-tyrosine kinase families categorized to date. The kinase activity and tyrosine phosphorylation of pp125FAK are induced by beta 1 and beta 3 integrin-mediated cell adherence or aggregation. pp125FAK is also a tyrosine phosphorylation substrate in v-src-transformed cells and is localized to focal adhesion contracts of adherent fibroblasts and carcinoma cells. In this report, we have transiently expressed in COS cells a transmembrane-anchored chimeric receptor kinase, CD2FAK, consisting of CD2 and pp125FAK. We analyzed its kinase activity and tyrosine phosphorylation and compared to those of pp125FAK. We found that CD2FAK exhibited constitutive kinase activity and a high basal tyrosine phosphorylation level when COS transfectants were suspended in serum-free media. The kinase activity of CD2FAK was similarly up-regulated upon beta 1 integrin-mediated cell adherence as the endogenous pp125FAK. Both CD2FAK and pp125FAK appeared to be active as autophosphorylating kinases as shown by mutation of the ATP binding site. We determined the major tyrosine phosphorylation site, Tyr397, identical for both the constitutively activated CD2FAK and pp125FAK in response to beta 1 integrin-mediated cell adherence by site-directed mutagenesis. Deletions of the NH2- or the COOH-terminal noncatalytic domain of FAK, including Tyr397 did not lead to abolition of the kinase activity of pp125FAK or CD2FAK. Taken together, CD2FAK exhibits properties of an activated pp125FAK and the kinase activity does not appear to require tyrosine phosphorylation in vitro or in vivo.

Animals↗
PubMed1994

Genetics of bitter perception in mice.

Inbred and congenic strains exhibited several patterns of relative sensitivity to bitter tastants in 48-h, two-bottle preference tests. With segregation analyses of descendents of crosses between contrasting strains, these patterns suggested at least three genetic loci influencing bitter perception. The extensively characterized Soa (sucrose octaacetate) locus underlies one pattern. Variation at this locus had pleiotropic effects on avoidance of other acetylated sugars, plus such structurally dissimilar bitter tastants as brucine, denatonium benzoate, and quinine sulfate. Unlike SOA, however, sensitivity to quinine sulfate was polygenically determined, and produced a second characteristic pattern. At least one, possibly several, additional unlinked loci contributed to quinine differences. Phenylthiocarbamide (PTC) aversion differences exemplified a third pattern. Segregation consistent with monogenic control of PTC aversion has been reported, and within segregating populations PTC aversion did not covary with SOA or quinine sulfate avoidance. Variants of the three major patterns may be useful for analysis of specific mechanisms. While both showed the SOA pattern, strychnine differences were markedly smaller than brucine (dimethoxystrychnine) differences. Likewise, a hop extract containing primarily iso-alpha acids (e.g., isohumulone) produced an SOA-like pattern, while an extract with nonisomerized alpha-acids (e.g., humulone) did not.

Animals↗
PubMed1994

Generation of inositol phosphates in bitter taste transduction.

It is probable that there is a diversity of mechanisms involved in the transduction of bitter taste. One of these mechanisms uses the second messengers, inositol 1,4,5-trisphosphate (IP3) and diacylglycerol (DAG). Partial membrane preparations from circumvallate and foliate taste regions of mice tongues responded to the addition of known bitter taste stimuli by increasing the amount of inositol phosphates produced after 30 s incubation. Addition of both the bitter stimulus, sucrose octaacetate and the G-protein stimulant, GTP gamma S, led to an enhanced production of inositol phosphates compared with either alone. Pretreatment of the tissue samples with pertussis toxin eliminated all response to sucrose octaacetate plus GTP gamma S, whereas pretreatment with cholera toxin was without effect. Western blots of solubilized tissue from circumvallate and foliate regions probed with antibodies to the alpha-subunit of several types of G-proteins revealed bands reactive to antibodies against G alpha i1-2 and G alpha o, with no apparent activity to antibodies against G alpha i3. Given the results from the immunoblots and those of the toxin experiments, it is proposed that the transduction of the bitter taste of sucrose octaacetate in mice involves a receptor-mediated activation of a Gi-type protein which activates a phospholipase C to produce the two second messengers, IP3 and DAG.

Animals↗
PubMed1994

Hydrolysis of sucrose octa-acetate: qualitative differences in taster and demistaster avoidance phenotypes.

Calcium hydroxide and sodium hydroxide were used to hydrolyse sucrose octa-acetate (SOA) as a means of evaluating the taster (Soaa) and demitaster (Soac) allelic phenotypes of the genetic locus Soa. The SWR/J (taster) inbred strain and the B6.SW Soaa (taster) congenic strain were demonstrated to cease avoiding upon nearly complete hydrolysis of 10(-5) M SOA with calcium hydroxide or sodium hydroxide and of 10(-4) M SOA with calcium hydroxide. The BALB/cByJ, C3HeB/FeJ and DBA/2J (demitaster) inbred strains were demonstrated to cease avoiding after only a partial hydrolysis of 10(-3) M SOA using calcium hydroxide. It is suggested that specificity for the number or placement of the acetates of SOA underlies the difference between the taster and demitaster phenotypes.

Animals↗
PubMed1993

Preparing for parent-held child health records.

On 1 October 1992 health visitors in the Portsmouth and South Hampshire health district introduced parent-held child health records. The following reports by key participants in this major change in health visiting practice underline the importance of training to prepare staff for the challenge. Partnership between field staff and management is key if the principles of openness and trust underlying the concept of the parent-held record are to be implemented in practice.

Child↗
PubMed1992

Chromosome mapping of Soa, a gene influencing gustatory sensitivity to sucrose octaacetate in mice.

Strain distribution patterns among recombinant inbred strains suggested that a locus influencing taste sensitivity to sucrose octaacetate was on chromosome 6. A location for Soa was established by linkage analysis of behavioral and electrophoretic data from outbred and congenic strains and from test-cross progeny. Haplotyping of 41 outbred CFW-Cr animals with a cDNA probe showed perfect cosegregation of Soa and Prp, a gene for salivary proline-rich proteins. Five of twelve B6.SW-Soaa strains were found to retain Ldr-1, lactate dehydrogenase regulator-1, on chromosome 6 as an allelic passenger from the SWR/J donor strain (source of the Soaa Taster allele). Centimorgan distance was estimated using the ABP/Le linkage-testing strain (non-Taster, Soab) and the SWR/J strain (Taster, Soaa) in a testcross breeding system. The data are consistent with a position for the Soa locus on mouse chromosome 6, 62 cM from the centromere.

Animals↗