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The selective isolation of an active-site histidine peptide from chymotrypsin-alpha by diagonal peptide 'mapping'. An N-tau-carboxymethylhistidine diagonal peptide "mapping.".

1. The selective isolation of an ;active' histidine peptide from reduced and cyanoethylated chymotrypsin-alpha inhibited with Tos-Phe-CH(2)Cl (l-1-tosylamido-2-phenylethyl chloromethyl ketone) was obtained with a His(tauCm) (N(tau)-carboxymethylhistidine) diagonal peptide-;mapping' technique. Performic acid vapours, used between the first and second dimensions of the diagonal peptide ;map', resulted in a peracid rearrangement of the alkylated (Tos-Phe-CH(2))-histidine-57 residue into an N(tau)-carboxymethylhistidine residue. The consequent change in electrophoretic mobility allowed isolation of peptides that contained the ;active' histidine. 2. Peptides containing methionine or S-cyanoethylcysteine were oxidized to their sulphones during the treatment. Peptides in which these residues were N-terminal were selectively isolated on the basis of the change in electrophoretic mobility at pH6.5 which was due to the depression of the pK of the terminal amino group by the inductive effect of the sulphonyl group. 3. An attempt to apply the method to subtilisin BPN' inhibited with l-1-benzyloxycarbonylamido-2-phenylethyl bromomethyl ketone failed to yield a peptide containing N(tau)-carboxymethylhistidine, although peptides containing N-terminal methionine were isolated by the procedure.

Amino Acid Sequence↗

Mapping the interacting regions between troponins T and C. Binding of TnT and TnI peptides to TnC and NMR mapping of the TnT-binding site on TnC.

Muscular contraction is triggered by an increase in calcium concentration, which is transmitted to the contractile proteins by the troponin complex. The interactions among the components of the troponin complex (troponins T, C, and I) are essential to understanding the regulation of muscle contraction. While the structure of TnC is well known, and a model for the binary TnC.TnI complex has been recently published (Tung, C.-S., Wall, M. E., Gallagher, S. C., and Trewhella, J. (2000) Protein Sci. 9, 1312-1326), very little is known about TnT. Using non-denaturing gels and NMR spectroscopy, we have analyzed the interactions between TnC and five peptides from TnT as well as how three TnI peptides affect these interactions. Rabbit fast skeletal muscle peptide TnT-(160-193) binds to TnC with a dissociation constant of 30 +/- 6 microm. This binding still occurs in the presence of TnI-(1-40) but is prevented by the presence of TnI-(56-115) or TnI-(96-139), both containing the primary inhibitory region of TnI. TnT-(228-260) also binds TnC. The binding site for TnT-(160-193) is located on the C-terminal domain of TnC and was mapped to the surface of TnC using NMR chemical shift mapping techniques. In the context of the model for the TnC.TnI complex, we discuss the interactions between TnT and the other troponin subunits.

Animals↗

Comparison of theoretical denaturation maps of phiX174 and SV40 with their gene maps.

When the theoretical denaturation maps of phiX174 and SV40 are compared with their gene maps, it is observed that the beginning and the end of each gene in these two DNA's fall in a region of lower melting temperatures. Local (A+T)-contents evaluated from the known sequences at these regions support the above implication that the beginnings and the ends of nearly all the genes in phiX174 and SV40 are relatively rich in (A+T)-content.

Adenine↗

Phase order in chaotic maps and in coupled map lattices

By defining a direction phase as the direction of two sequential iterations of the logistic map, a transition of a net direction phase M from zero to a finite value as the parameter &mgr; increases is found. Near the transition point &mgr;(0) a scaling M approximately (&mgr;-&mgr;(0))(alpha) with alpha = 0.5 is obtained. The order state of the direction phases in a coupled map lattice is also studied. A phase synchronization of the direction phases is found although the lattices still remain chaotic.

Journal Article↗

A restriction map of cauliflower mosaic virus DNA (strain PV 147). Mapping of the cleavage sites of HhaI, SacI, AvaI, PvuII, PstI, XbaI, EcoRI, Bg/II, HincII, HpaII and HindII + III.

The virion-extracted DNA (Mr5 x 10(6)) of cauliflower mosaic virus (CaMV) has three single-stranded interruptions. The mapping of this DNA using eleven restriction endonucleases (HhaI, SacI, AvaI, PvuII, PstI, XbaI, EcoRI, Bg/II, HincII, HpaII and HindII + III) is reported here. The existence of the three single-stranded breaks complicates the identification and the molecular weight determination of fragments produced by HpaII, HindIII and HindII + III. Indeed the electrophoretic mobility of some fragments in which a single-stranded discontinuity is located is modified, and the fluorescence of ethidium bromide complexed with these fragments is reduced as compared to that observed for the other fragments existing in a molar ratio. These drawbacks were overcome by performing experiments of nick-translation of CaMV DNA with Escherichia coli DNA polymerase I. FRom the data it follows that the CaMV DNA molecule bears bears 1 site for HhaI and SacI, 2 for AvaI and PvuII, 3 for PstI, 4 for XbaI, 5 for EcoRI, 6 for Bg/II and HincII, 11 for HpaII and 15 for HindII + III. The corresponding fragments have all been ordered and precisely located providing a suitable map for further investigations connected with the study of the fine structure and the function of the CaMV genome.

DNA Restriction Enzymes↗

Repression of hyphal proteinase expression by the mitogen-activated protein (MAP) kinase phosphatase Cpp1p of Candida albicans is independent of the MAP kinase Cek1p.

Cpp1p is a putative mitogen-activated protein (MAP) kinase phosphatase that suppresses Candida albicans hyphal formation at 25 degrees C through its probable substrate, the Cek1p filamentation MAP kinase. Here we report that expression of the serum-induced genes SAP4-6 and HYR1 increased several fold in hyphal forms of a cpp1/cpp1 null mutant, while the rate and extent of hyphal development up to 5 h were normal. Therefore, we provide evidence that Cpp1p represses hyphal gene expression by acting through a Cek1p-independent mechanism. SAP4-6 and HYR1 transcripts were undetectable in a null mutant of another key regulator of filamentation, Efg1p; thus, Efg1p and Cpp1p oppose each other during the expression of these genes in hyphal forms.

Aspartic Acid Endopeptidases↗

Physical map of the Salmonella typhimurium histidine transport operon: correlation with the genetic map.

A detailed restriction map of a 12.4-kilobase EcoRI fragment of Salmonella typhimurium deoxyribonucleic acid (DNA) containing the entire histidine transport operon and the argT gene is presented. Subclones of specific regions of the transport operon of S. typhimurium were constructed in plasmid vectors. An accurate correlation between the restriction map and the location of genetically defined deletions was obtained by hybridizing restriction digests of chromosomal DNA from strains carrying each deletion with cloned transport operon DNA as a probe. These data were used to position the histidine transport genes on the cloned 12.4-kilobase fragment of DNA.

Biological Transport↗

Suppression subtractive hybridization (SSH) identifies prolactin stimulation of p38 MAP kinase gene expression in Nb2 T lymphoma cells: molecular cloning of rat p38 MAP kinase.

Suppression Subtractive Hybridization (SSH) has been used to compare rat Nb2 cells treated with prolactin for 1 hour with untreated cells. This new method for identifying differentially expressed genes showed that the mRNAs for at least three genes were elevated by such treatment, including a p38 mitogen activated protein (MAP) kinase. The p38 MAP kinase was cloned and the full length cDNA sequence was determined.

Animals↗

Fine-mapping, mutation analyses, and structural mapping of cerebrotendinous xanthomatosis in U.S. pedigrees.

Cerebrotendinous xanthomatosis (CTX) is a rare autosomal recessive disorder of bile acid biosynthesis. Clinically, CTX patients present with tendon xanthomas, juvenile cataracts, and progressive neurological dysfunction and can be diagnosed by the detection of elevated plasma cholestanol levels. CTX is caused by mutations affecting the sterol 27-hydroxylase gene (CYP27 ). CTX has been identified in a number of populations, but seems to have a higher prevalence in the Japanese, Sephardic Jewish, and Italian populations. We have assembled 12 previously unreported pedigrees from the United States. The CYP27 locus had been previously mapped to chromosome 2q33-qter. We performed linkage analyses and found no evidence of genetic heterogeneity. All CTX patients showed segregation with the CYP27 locus, and haplotype analysis and recombinant events allowed us to precisely map CYP27 to chromosome 2q35, between markers D2S1371 and D2S424. Twenty-three mutations were identified from 13 probands analyzed thus far; 11 were compound heterozygotes and 2 had homozygous mutations. Of these, five are novel mutations [Trp100Stop, Pro408Ser, Gln428Stop, a 10-base pair (bp) deletion in exon 1, and a 2-bp deletion in exon 6 of the CYP27 gene]. Three-dimensional structural modeling of sterol 27-hydroxylase showed that, while the majority of the missense mutations disrupt the heme-binding and adrenodoxin-binding domains critical for enzyme activity, two missense mutations (Arg94Trp/Gln and Lys226Arg) are clearly located outside these sites and may identify a potential substrate-binding or other protein contact site.

Adolescent↗

[Physical mapping of Streptomyces coelicolor Ae(2) actinophages. IV. Partial denaturation maps].

By measuring temperature transition profiles evidence was obtained that DNA of actinophage phiC31 has a random base distribution and the content of GC pairs is 63%. The denaturation maps of the DNA molecules of actinophages phiC31c28, phiC43del and phiC62 are similar and characteristic of these random base distributions. Main peaks are located at positions: 0.03, 0.25, 0.33, 0.53 and 0.99 from the left end (in relative units). Positions of the regions deleted in phages phiC31c28 and phiC43del were established in respect to phage phiC62 genome and shown not to coincide with the position of the denaturation peaks on the phiC62 DNA map. It seems unlikely that AT rich regions are preferrable ones for deletions in actinophage DNAs.

Bacteriophages↗

MAP kinase kinase 6-p38 MAP kinase signaling cascade regulates cyclooxygenase-2 expression in cardiac myocytes in vitro and in vivo.

Cyclooxygenase-2 (COX-2) catalyzes the rate-limiting step in delayed prostaglandin biosynthesis. The purpose of this study was to evaluate the role of the MAP kinase kinase 6 (MKK6)-p38 MAPK signaling cascade in the regulation of myocardial COX-2 gene expression, in vitro and in vivo. RT-PCR analysis identified p38alpha and p38beta2 MAPK mRNA in rat cardiac myocytes. Interleukin-1beta induced the phosphorylation of p38alpha and p38beta2 MAPK in cardiomyocytes and stimulated RNA polymerase II binding to the COX-2 promoter, COX-2 transcription, COX-2 protein synthesis, and prostaglandin E2 (PGE2) release. Infecting cardiomyocytes with adenoviruses that encode mutant, phosphorylation-resistant MKK6 or p38beta2 MAPK inhibited interleukin-1beta-induced p38 MAPK activation, COX-2 gene expression, and PGE2 release. Treatment with the p38alpha and p38beta2 MAPK inhibitor, SB202190, attenuated interleukin-1beta-induced COX-2 transcription and accelerated the degradation of COX-2 mRNA. Cells infected with adenoviruses encoding wild-type or constitutively activated MKK6 or p38beta2 MAPK, in the absence of interleukin-1beta, exhibited increased cellular p38 MAPK activity, COX-2 mRNA expression, and COX-2 protein synthesis, which was blocked by SB202190. In addition, elevated levels of COX-2 protein were identified in the hearts of transgenic mice with cardiac-restricted expression of wild-type or constitutively activated MKK6, in comparison with nontransgenic littermates. These results provide direct evidence that MKK6 mediated p38 MAPK activation is necessary for interleukin-1beta-induced cardiac myocyte COX-2 gene expression and PGE2 biosynthesis in vitro and is sufficient for COX-2 gene expression by cardiac myocytes in vitro and in vivo.

Animals↗

Disease mapping models: an empirical evaluation. Disease Mapping Collaborative Group.

The analysis of small area disease incidence has now developed to a degree where many methods have been proposed. However, there are few studies of the relative merits of the methods available. While many Bayesian models have been examined with respect to prior sensitivity, it is clear that wider comparisons of methods are largely missing from the literature. In this paper we present some preliminary results concerning the goodness-of-fit of a variety of disease mapping methods to simulated data for disease incidence derived from a range of models. These simulated models cover simple risk gradients to more complex true risk structures, including spatial correlation. The main general results presented here show that the gamma-Poisson exchangeable model and the Besag, York and Mollie (BYM) model are most robust across a range of diverse models. Mixture models are less robust. Non-parametric smoothing methods perform badly in general. Linear Bayes methods display behaviour similar to that of the gamma-Poisson methods.

Algorithms↗

Fine mapping of the cystinosis gene using an integrated genetic and physical map of a region within human chromosome band 17p13.

The cystinosis gene has been reported to reside in a 3.1 cM region of chromosome 17p13 flanked by markers D17S1828 and D17S1798. We created a yeast artificial chromosome (YAC) contig between these markers and report here an integrated genetic and physical map which will aid in the identification of other genes in this area. Using one pertinent YAC clone, 898A10, we identified new polymorphic markers in the cystinosis gene region. One such marker, D17S2167, was localized by radiation hybrid analysis to within 10.2 cR8000 of D17S1828. Haplotype analysis in two separate informative families revealed recombination events which placed the cystinosis gene between markers D17S1828 and D17S2167, an area estimated to be 187-510 kb in size. This dramatic narrowing of the cystinosis gene region permits the creation of a P1 or cosmid contig across the area of interest. The ultimate cloning of the cystinosis gene should eventually reveal how a functional lysosomal transport protein is synthesized, targetted, processed, and integrated into the lysosomal membrane.

Base Sequence↗

Inhibition of p38 MAP kinase activity up-regulates multiple MAP kinase pathways and potentiates 1,25-dihydroxyvitamin D(3)-induced differentiation of human leukemia HL60 cells.

Differentiation therapy for neoplastic diseases has potential for supplementing existing treatment modalities but its implementation has been slow. One of the reasons is the lack of full understanding of the complexities of cellular pathways through which signals for differentiation lead to cell maturation. This was addressed in this study using HL60 cells, a well-established model of differentiation of neoplastic cells. SB 203580 and SB 202190, specific inhibitors of a signaling protein p38 MAP kinase, were found to markedly accelerate monocytic differentiation of HL60 cells induced by low concentrations of 1,25-dihydroxyvitamin D(3) (1,25D(3)). Surprisingly, inhibition of p38 activity resulted in sustained enhancement of p38 phosphorylation and of its in vitro activity in the absence of the inhibitor, indicating up-regulation of the upstream components of the p38 pathway. In addition, SB 203580 or SB 202190 treatment of HL60 cells resulted in a prolonged activation of the JNK and, to a lesser extent, the ERK pathways. The data are consistent with the hypothesis that in HL60 cells an interruption of a negative feedback loop from a p38 target activates a common regulator of multiple MAPK pathways. The possibility also exists that JNK and/or ERK pathways amplify a differentiation signal provided by 1,25D(3).

Calcitriol↗

Isolation and genetic mapping of two novel members of the murine Wnt gene family, Wnt11 and Wnt12, and the mapping of Wnt5a and Wnt7a.

The murine Wnt genes are implicated in the control of a variety of developmental processes. Using a PCR-based approach, we have isolated two novel members of the murine Wnt gene family, Wnt11 and Wnt12. These cDNAs display an amino acid sequence identity of between 38 and 49% with all other murine Wnts over the regions that we have isolated. In addition, two previously described Wnt genes, Wnt5a and Wnt7a, were detected in RT-PCR products. Interspecific crosses were used to demonstrate close linkage between Wnt12 and Wnt1 on Chromosome (Chr) 15. Wnt7a was mapped to mouse Chr 6, Wnt5a to the centromeric region of Chr 14, and Wnt11 to Chr7.

Amino Acid Sequence↗

Cyclophilin A, the major intracellular receptor for the immunosuppressant cyclosporin A, maps to chromosome 7p11.2-p13: four pseudogenes map to chromosomes 3, 10, 14, and 18.

Cyclophilin A (CyP-A), the major intracellular receptor for the immunosuppressant cyclosporin A (CsA), is a member of the immunophilin class of proteins, which all possess peptidyl-prolyl cis-trans isomerase activity and, therefore, are believed to be involved in protein folding and/or intracellular protein transport. The CyP-A protein is encoded by a single gene; in addition, 15 pseudogenes have been identified. Recently, specific binding of CyP-A to the human immunodeficiency virus type 1 (HIV-1) gag protein has been reported. Interestingly, this interaction can be inhibited by the immunosuppressant CsA and also by nonimmunosuppressive, CyP-A-binding CsA derivatives, which were also shown to exhibit potent anti-HIV-1 activity. Results thus indicate that CyP-A may have an essential function in HIV-1 replication. Using a panel of somatic rodent-human cell hybrids and PCR technology, we localized the coding cyclophilin A gene (PPIA) on chromosome 7 and four pseudogenes (PPIP2, PPIP3, PPIP4, and PPIP6) on chromosomes 14, 10, 18, and 3, respectively. Using chromosome 7 and chromosome 10 deletion hybrid panels, we were able to localize further the coding gene to the region 7p11.2-p13, as confirmed by fluorescence in situ hybridization analysis, and one pseudogene (PPIP3) to the region 10q11.2-q23. This is the first report on the regional mapping of members of the CyP-A gene family.

Amino Acid Isomerases↗

Identification of a psoriasis susceptibility candidate gene by linkage disequilibrium mapping with a localized single nucleotide polymorphism map.

Psoriasis is a chronic inflammatory disease of the skin with both genetic and environmental risk factors. Here we describe the creation of a single-nucleotide polymorphism (SNP) map spanning 900-1200 kb of chromosome 3q21, which had been previously recognized as containing a psoriasis susceptibility locus, PSORS5. We genotyped 644 individuals, from 195 Swedish psoriatic families, for 19 polymorphisms. Linkage disequilibrium (LD) between marker and disease was assessed using the transmission/disequilibrium test (TDT). In the TDT analysis, alleles of three of these SNPs showed significant association with disease (P<0.05). A 160-kb interval encompassing these three SNPs was sequenced, and a coding sequence consisting of 13 exons was identified. The predicted protein shares 30-40% homology with the family of cation/chloride cotransporters. A five-marker haplotype spanning the 3' half of this gene is associated with psoriasis to a P value of 3.8<10(-5). We have called this gene SLC12A8, coding for a member of the solute carrier family 12 proteins. It belongs to a class of genes that were previously unrecognized as playing a role in psoriasis pathogenesis.

Amino Acid Sequence↗