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排序方式: 共有228条查询结果,搜索用时 15 毫秒
1.
Monomorphism in humans and sequence differences among higher primates for a sequence tagged site (STS) in homeo box cluster 2 as assayed by denaturing gradient electrophoresis. 总被引:2,自引:2,他引:0
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G Ruano M R Gray T Miki A C Ferguson-Smith F H Ruddle K K Kidd 《Nucleic acids research》1990,18(5):1314
2.
G Ruano E M Pagliaro T R Schwartz K Lamy D Messina R E Gaensslen H C Lee 《BioTechniques》1992,13(2):266-274
Heat-soaked PCR (HS-PCR) is a method for enhancing amplification performed by heating the DNA sample at 94 degrees C in 90 microliters 1.1 x buffer for 30 min. A 10-microliters bolus of concentrated (10x) deoxynucleotides, Taq DNA polymerase and primers prepared without buffer is then added just prior to thermal cycling. We have investigated the application of this method in a variety of forensically important DNA samples and compared it with regular PCR (R-PCR). DNA samples extracted from bone, postmortem tissues, bloodstains and hair contained low concentrations of human DNA or were contaminated with either non- human DNA or hemoglobin degradation products. Optimal conditions for HS-PCR were determined for the 3' ApoB VNTR locus and applied to a centromeric repeat element and to a single-copy locus. HS-PCR consistently and reproducibly enhanced product yield and specificity over R-PCR at all three loci in the entire set of DNA samples. HS-PCR was also effective in overcoming the inhibitory effect of hemoglobin at concentrations that fully impeded R-PCR. 相似文献
3.
We have broadly defined the DNA regions regulating esterase6 activity in
several life stages and tissue types of D. melanogaster using P-
element-mediated transformation of constructs that contain the esterase6
coding region and deletions or substitutions in 5' or 3' flanking DNA.
Hemolymph is a conserved ancestral site of EST6 activity in Drosophila and
the primary sequences regulating its activity lie between -171 and -25 bp
relative to the translation initiation site: deletion of these sequences
decrease activity approximately 20-fold. Hemolymph activity is also
modulated by four other DNA regions, three of which lie 5' and one of which
lies 3' of the coding region. Of these, two have positive and two have
negative effects, each of approximately twofold. Esterase6 activity is
present also in two male reproductive tract tissues; the ejaculatory bulb,
which is another ancestral activity site, and the ejaculatory duct, which
is a recently acquired site within the melanogaster species subgroup.
Activities in these tissues are at least in part independently regulated:
activity in the ejaculatory bulb is conferred by sequences between -273 and
-172 bp (threefold decrease when deleted), while activity in the
ejaculatory duct is conferred by more distal sequences between -844 and
-614 bp (fourfold decrease when deleted). The reproductive tract activity
is further modulated by two additional DNA regions, one in 5' DNA (-613 to
-284 bp; threefold decrease when deleted) and the other in 3' DNA (+1860 to
+2731 bp; threefold decrease when deleted) that probably overlaps the
adjacent esteraseP gene. Collating these data with previous studies
suggests that expression of EST6 in the ancestral sites is mainly regulated
by conserved proximal sequences while more variable distal sequences
regulate expression in the acquired ejaculatory duct site.
相似文献
4.
Litman GW; Rast JP; Shamblott MJ; Haire RN; Hulst M; Roess W; Litman RT; Hinds- Frey KR; Zilch A; Amemiya CT 《Molecular biology and evolution》1993,10(1):60-72
Immunoglobulins are encoded by a large multigene system that undergoes
somatic rearrangement and additional genetic change during the development
of immunoglobulin-producing cells. Inducible antibody and antibody-like
responses are found in all vertebrates. However, immunoglobulin possessing
disulfide-bonded heavy and light chains and domain-type organization has
been described only in representatives of the jawed vertebrates. High
degrees of nucleotide and predicted amino acid sequence identity are
evident when the segmental elements that constitute the immunoglobulin gene
loci in phylogenetically divergent vertebrates are compared. However, the
organization of gene loci and the manner in which the independent elements
recombine (and diversify) vary markedly among different taxa. One striking
pattern of gene organization is the "cluster type" that appears to be
restricted to the chondrichthyes (cartilaginous fishes) and limits
segmental rearrangement to closely linked elements. This type of gene
organization is associated with both heavy- and light-chain gene loci. In
some cases, the clusters are "joined" or "partially joined" in the germ
line, in effect predetermining or partially predetermining, respectively,
the encoded specificities (the assumption being that these are expressed)
of the individual loci. By relating the sequences of transcribed gene
products to their respective germ-line genes, it is evident that, in some
cases, joined-type genes are expressed. This raises a question about the
existence and/or nature of allelic exclusion in these species. The
extensive variation in gene organization found throughout the vertebrate
species may relate directly to the role of intersegmental
(V<==>D<==>J) distances in the commitment of the individual
antibody-producing cell to a particular genetic specificity. Thus, the
evolution of this locus, perhaps more so than that of others, may reflect
the interrelationships between genetic organization and function.
相似文献
5.
Gemma Aragonès Kalavathi Dasuri Opeoluwa Olukorede Sarah G. Francisco Carol Renneburg Caroline Kumsta Malene Hansen Shun Kageyama Masaaki Komatsu Sheldon Rowan Jonathan Volkin Michael Workman Wenxin Yang Paula Daza Diego Ruano Helena Dominguez‐Martín José Antonio Rodríguez‐Navarro Xue‐Liang Du Michael A. Brownlee Eloy Bejarano Allen Taylor 《Aging cell》2020,19(11)
6.
7.
Schistosomiasis vector snails are subjected to extreme seasonal changes, particularly in ephemeral rivers and lentic waterbodies. In the tropics, aestivation is one of the adaptive strategies for survival and is used by snails in times of extremely high temperatures and desiccation. Aestivation therefore plays an important role in maintaining the transmission of schistosomiasis. This review assesses the possible impacts of climate change on the temporal and spatial distribution of schistosomiasis-transmitting snails with special emphasis on aestivation, and discusses the effect of schistosome infection on aestivation ability. The impacts of parasite development on snails, as well as physiological changes, are discussed with reference to schistosomiasis transmission. This review shows that schistosome-infected snails have lower survival rates during aestivation, and that those that survive manage to get rid of the infection. In general, snail aestivation ability is poor and survival chances diminish with time. Longer dry periods result in fewer, as well as uninfected, snails. However, the ability of the surviving snails to repopulate the habitats is high. 相似文献
8.
Attenuation of pattern recognition receptor signaling is mediated by a MAP kinase kinase kinase
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Sharon C Mithoe Christina Ludwig Michiel JC Pel Mara Cucinotta Alberto Casartelli Malick Mbengue Jan Sklenar Paul Derbyshire Silke Robatzek Corné MJ Pieterse Ruedi Aebersold Frank LH Menke 《EMBO reports》2016,17(3):441-454
Pattern recognition receptors (PRRs) play a key role in plant and animal innate immunity. PRR binding of their cognate ligand triggers a signaling network and activates an immune response. Activation of PRR signaling must be controlled prior to ligand binding to prevent spurious signaling and immune activation. Flagellin perception in Arabidopsis through FLAGELLIN‐SENSITIVE 2 (FLS2) induces the activation of mitogen‐activated protein kinases (MAPKs) and immunity. However, the precise molecular mechanism that connects activated FLS2 to downstream MAPK cascades remains unknown. Here, we report the identification of a differentially phosphorylated MAP kinase kinase kinase that also interacts with FLS2. Using targeted proteomics and functional analysis, we show that MKKK7 negatively regulates flagellin‐triggered signaling and basal immunity and this requires phosphorylation of MKKK7 on specific serine residues. MKKK7 attenuates MPK6 activity and defense gene expression. Moreover, MKKK7 suppresses the reactive oxygen species burst downstream of FLS2, suggesting that MKKK7‐mediated attenuation of FLS2 signaling occurs through direct modulation of the FLS2 complex. 相似文献
9.
Wang Q Montmain G Ruano E Upadhyaya M Dudley S Liskay RM Thibodeau SN Puisieux A 《Human genetics》2003,112(2):117-123
DNA mismatch repair (MMR) is the process by which incorrectly paired DNA nucleotides are recognized and repaired. A germline mutation in one of the genes involved in the process may be responsible for a dominantly inherited cancer syndrome, hereditary nonpolyposis colon cancer. Cancer progression in predisposed individuals results from the somatic inactivation of the normal copy of the MMR gene, leading to a mutator phenotype affecting preferentially repeat sequences (microsatellite instability, MSI). Recently, we identified children with a constitutional deficiency of MMR activity attributable to a mutation in the h MLH1 gene. These children exhibited a constitutional genetic instability associated with clinical features of de novo neurofibromatosis type 1 (NF1) and early onset of extracolonic cancer. Based on these observations, we hypothesized that somatic NF1 gene mutation was a frequent and possibly early event in MMR-deficient cells. To test this hypothesis, we screened for NF1 mutations in cancer cells. Genetic alterations were identified in five out of ten tumor cell lines with MSI, whereas five MMR-proficient tumor cell lines expressed a wild-type NF1 gene. Somatic NF1 mutations were also detected in two primary tumors exhibiting an MSI phenotype. Finally, a 35-bp deletion in the murine Nf1 coding region was identified in mlh1-/- mouse embryonic fibroblasts. These observations demonstrate that the NF1 gene is a mutational target of MMR deficiency and suggest that its inactivation is an important step of the malignant progression of MMR-deficient cells. 相似文献
10.
Antiproliferative effect of nitric oxide on epidermal growth factor-responsive human neuroblastoma cells 总被引:4,自引:0,他引:4
Murillo-Carretero M Ruano MJ Matarredona ER Villalobo A Estrada C 《Journal of neurochemistry》2002,83(1):119-131
Addition of nitric oxide (NO) donors to NB69 neuroblastoma cells produced a cGMP-independent decrease in cell proliferation, without affecting cell viability or apoptosis. The potency of short half-life NO donors was higher when cell proliferation was stimulated by epidermal growth factor (EGF), as compared with cultures exposed to fetal calf serum (FCS). Immunoprecipitation and western blot analysis of the EGF receptor (EGFR) revealed a significant reduction of its EGF-induced tyrosine phosphorylation in cells treated with the NO donor 2-(N,N-diethylamino)-diazenolate-2-oxide (DEA-NO). When total cell lysates were subjected to western blotting, we observed that DEA-NO also reduced tyrosine phosphorylation in EGF-activated phosphoproteins, but not in those proteins whose tyrosine phosphorylation was evident in the absence of EGF. The effect of NO on EGFR transphosphorylation was concentration-dependent and transient, with a total recovery observed between 1.5 and 3 h after addition of DEA-NO to the cells. When cells were incubated for 15 min with DEA-NO and then washed, the EGFR transphosphorylation returned to control levels immediately, indicating that the interaction of NO with the receptor molecule was fully reversible. NB69 cells expressed both the neuronal and the inducible isoforms of NO synthase (NOS) when cultured in the presence of FCS; under this condition, the NOS inhibitor, N(omega)-nitro-L-arginine methyl ester, produced a small but significant increase in cell proliferation. The results suggest that NO is an endogenous antimitotic agent and that its interaction with EGFR contributes to cytostasis in NB69 cells. 相似文献