共查询到20条相似文献,搜索用时 625 毫秒
1.
Dana-Lynn T. Koomoa Mark W. Musch Leon Goldstein 《The Journal of membrane biology》2006,208(3):241-250
When swollen, skate red blood cells increase permeability and allow efflux of a number of solutes, including taurine. Hypoosmosis-induced
taurine permeability appears to involve the red cell anion exchanger. However, three isoforms have been cloned from these
cells. Therefore, to determine the ability of the individual isoform skate anion exchanger 1 (skAE1) to mediate hypoosmosis-induced
taurine permeability as well as associated regulatory events, skAE1 was expressed in Xenopus oocytes. This study focused on investigating the role of tyrosine kinases and lipid rafts in the regulation of the channel.
The results showed that tyrosine kinase inhibitors and lipid raft-disrupting agents inhibited the volume-sensitive organic
osmolyte channel while protein tyrosine phosphatase inhibitors activated the channel in oocytes expressing skAE1. To study
the role of lipid rafts in the activation of the volume-sensitive organic osmolyte channel, the cellular localization of skAE1
was investigated. Also, the role of tyrosine kinases was investigated by examining the tyrosine phosphorylation state of skAE1.
Hypoosmotic stress induced mobilization of skAE1 into light membranes and the cell surface as well as tyrosine phosphorylation
of skAE1. These events are involved in the activation of the volume-sensitive organic osmolyte channel in Xenopus oocytes expressing skAE1. 相似文献
2.
Koomoa DL Musch MW Goldstein L 《Journal of experimental zoology. Part A, Comparative experimental biology》2005,303(4):319-322
The aim of this study was to determine whether hypo-osmolarity, which activates taurine transport through the volume-sensitive organic osmolyte channel in skate (Raja erinacea) erythrocytes, also activates the organic osmolyte channel activity of skate AE1 (skAE1) expressed in oocytes. When Xenopus laevis oocytes expressing skAE1 were incubated in hypo-osmotic ND 96 (210 mOsm) media, taurine was transported at a significantly higher rate than when incubated in ND 96 (235 mOsm), which is iso-osmotic to Xenopus plasma. Therefore, hypo-osmotic stress is part of the activation mechanism of the organic osmolyte channel in skAE1 expressing oocytes. 相似文献
3.
Antoine AF Montpellier C Cailliau K Browaeys-Poly E Vilain JP Dubuisson J 《The Journal of membrane biology》2007,215(1):37-48
The Alphavirus Sindbis 6K protein is involved in several functions. It contributes to the processing and membrane insertion of E1 and PE2
viral envelope glycoproteins and to virus budding. It also permeabilizes Escherichia coli and mammalian cells. These viroporin-like properties have been proposed to help virus budding by modifying membrane permeabilities.
We expressed Sindbis virus 6K cRNA in Xenopus oocytes to further characterize the effect of 6K on membrane conductances and permeabilization. Although no intrinsic channel
properties were seen, cell shrinkage was observed within 24 h. Voltage-clamp experiments showed that 6K upregulated endogenous
currents: a hyperpolarization-activated inward current (I
in) and a calcium-dependent chloride current (I
Cl). 6K was located at both the plasma and the endoplasmic reticulum membranes. The plasma membrane current upregulation likely
results from disruption of the calcium homeostasis of the cell at the endoplasmic reticulum level. Indeed, 6K cRNA expression
induced reticular calcium store depletion and capacitative calcium entry activation. By experimental modifications of the
incubation medium, we showed that downstream of these events cell shrinkage resulted from a 6K -induced KCl efflux (I
Cl upregulation leads to chloride efflux, which itself electrically drives potassium efflux), which was responsible for an osmotic
water efflux. Our data confirm that 6K specifically triggers a sequential cascade of events that leads to cytoplasmic calcium
elevation and cell permeabilization, which likely play a role in the Sindbis virus life cycle. 相似文献
4.
When swollen, skate red blood cells increase permeability and allow efflux of a number of solutes, including taurine. Hypoosmosis-induced taurine permeability appears to involve the red cell anion exchanger. However, three isoforms have been cloned from these cells. Therefore, to determine the ability of the individual isoform skate anion exchanger 1 (skAE1) to mediate hypoosmosis-induced taurine permeability as well as associated regulatory events, skAE1 was expressed in Xenopus oocytes. This study focused on investigating the role of tyrosine kinases and lipid rafts in the regulation of the channel. The results showed that tyrosine kinase inhibitors and lipid raft-disrupting agents inhibited the volume-sensitive organic osmolyte channel while protein tyrosine phosphatase inhibitors activated the channel in oocytes expressing skAE1. To study the role of lipid rafts in the activation of the volume-sensitive organic osmolyte channel, the cellular localization of skAE1 was investigated. Also, the role of tyrosine kinases was investigated by examining the tyrosine phosphorylation state of skAE1. Hypoosmotic stress induced mobilization of skAE1 into light membranes and the cell surface as well as tyrosine phosphorylation of skAE1. These events are involved in the activation of the volume-sensitive organic osmolyte channel in Xenopus oocytes expressing skAE1. 相似文献
5.
Mounsey KE Dent JA Holt DC McCarthy J Currie BJ Walton SF 《Invertebrate neuroscience : IN》2007,7(3):149-156
Reports of ivermectin resistance in scabies mites raise concerns regarding the sustainability of mass intervention programs
for scabies worldwide and for the treatment of crusted scabies. Ligand gated ion channels (LGICs) are the primary targets
of ivermectin in invertebrates. We report the molecular characterisation of SsCl—a novel LGIC from Sarcoptes scabiei var. hominis. While SsCl shows sequence similarity to other LGICs, phylogenetic analysis does not suggest strong homology to conventional
glutamate, histamine or GABA gated channels. Instead, it is most similar to Drosophila pH-sensitive and group 1 clades. When expressed in Xenopus oocytes, SsCl forms a homomeric, pH-gated chloride channel that is irreversibly activated by ivermectin. These results provide
the first confirmation that this group of LGIC exists in arachnids, and suggest that SsCl may be an in vivo target of ivermectin
in S. scabiei. 相似文献
6.
Agonist activation of the hP2Y1 receptor expressed in Xenopus oocytes stimulated an endogenous voltage-gated ion channel, previously identified as the transient inward (Tin) channel. When human P2Y1 (hP2Y1) and skate P2Y (sP2Y) receptors were expressed in Xenopus oocytes, time-to-peak values (a measure of the response to membrane hyperpolarization) of the Tin channel were significantly reduced compared to oocytes expressing the hB1-bradykinin receptor or the rat M1-muscarinic (rM1) receptor. Differences in activation were also observed in the Tin currents elicited by various P2Y receptor subtypes. The time-to-peak values of the Tin channel in oocytes expressing the hP2Y4, hP2Y11, or hB1-bradykinin receptors were similar, whereas the channel had significantly shorter time-to-peak values in oocytes expressing either the hP2Y1 or sP2Y receptor. Amino acid substitutions at His-132, located in the third transmembrane domain (TM3) of the hP2Y1 receptor, delayed the onset of channel opening, but not the kinetics of the activation process. In addition, Zn2+ sensitivity was also dependent on the subtype of P2Y receptor expressed. Replacement of His-132 in the hP2Y1 receptor with either Ala or Phe increased Zn2+ sensitivity of the Tin current. In contrast, truncation of the C-terminal region of the hP2Y1 receptor had no affect on activation or Zn2+ sensitivity of the Tin channel. These results suggested that TM3 in the hP2Y1 receptor was involved in modulating ion channel function and blocker pharmacology of the Tin channel. 相似文献
7.
The Arabidopsis thaliana KAT1, an inward-rectifying potassium channel, shares molecular features with the Shaker family of outward rectifier K+ channels. The KAT1 amino-acid sequence reveals the presence of a positively charged S4 and a segment containing the TXGYGD signature sequence in the pore (P) region. To test whether the inward-rectifying properties of KAT1 are due to reverse orientation in the membrane, such that the voltage sensor is oriented in the opposite direction of the electric field compared with the Shaker K+ channel, we have inserted a flag epitope in the NH2 terminus or the S3–S4 loop. The KAT1 and tagged constructs expressed functional channels in whole cells, Xenopus oocytes and COS-7. The electrophysiological properties of both tagged constructs were similar to those of the wild type. Immunofluorescence with an antibody against the flag epitope and an anti-C terminal KAT1 determined the membrane localization of these epitopes and the orientation of the KAT1 channel in the membrane. Our data confirm that KAT1 in eukaryotic cells has an orientation similar to the Shaker K+ channel. 相似文献
8.
Epigenetic modifications of histone play important roles for regulation of cell activity, such as cell division, cell death,
and cell differentiation. A SET domain consisting of about 130 amino acids has lysine methyltransferase activity in the presence
of the cosubstrate S-adenosyl-methionine. More than 60 SET domain-containing proteins have been predicted in various organisms.
One of them, the SMYD family genes which contain a SET domain and a zinc-finger MYND domain are reported to regulate cell
cycle and muscle formation. Here we examined the expression and function of smyd1 and 2 in Xenopus. smyd1 and 2 were expressed in various muscle tissues. While smyd1 expression was observed mainly in cardiac muscle and skeletal muscle, smyd2 expression was done abundantly in skeletal muscle and face region. Moreover, by loss-of-function experiments using antisense
morpholino oligonucleotides, it was suggested that smyd1 and 2 related to muscle cells differentiation. 相似文献
9.
Kurisaki I Iwai T Yamashita M Kobayashi M Ito E Matsuoka I 《Cell and tissue research》2007,327(1):33-42
Pumilio is a sequence-specific RNA-binding protein that regulates translation from the relevant mRNA. The PUF-domain, the RNA-binding motif of Pumilio, is highly conserved across species. In the present study, we have identified two pumilio genes (pumilio-1 and pumilio-2) in rainbow trout and analyzed their expression patterns in its tissues. Pumilio-1 mRNA and pumilio-2A mRNA code for typical full length Pumilio proteins that contain a PUF-domain, whereas pumilio-2B mRNA is a splice variant of pumilio-2 and encodes a protein that lacks the PUF-domain. We have also identified a novel 72-bp exon that has not been reported in other animal species but is conserved in fish species. The insertion of this novel exon leads to the expression of an isoform of the Pumilio-2 protein with a slightly altered conformation of the PUF-domain. Pumilio-1 mRNA and pumilio-2A mRNA (irrespective of the presence of the 72-bp exon) are expressed in both the brain and ovaries at high levels, whereas pumilio-2B mRNA is expressed at low levels in all the rainbow trout tissues examined. Western blot analysis also indicates that the full length Pumilio proteins are expressed predominantly in the brain and ovaries. These data suggest that the Pumilio proteins have physiological roles and are involved in regulatory mechanisms in rainbow trout.This work was in part supported by a grant from the Akiyama Foundation to E.I. Nucleotide sequence data for rainbow trout pumilio-1 and pumilio-2 have been deposited in the DDBJ/EMBL/GenBank databases. 相似文献
10.
Vesta Skrodenytė-Arbačiauskienė Nijolė Kazlauskienė Milda Zita Vosylienė Tomas Virbickas 《Central European Journal of Biology》2012,7(5):878-885
Experimental studies of infection transmission via water from infected to healthy fish were conducted. The dark-brown bacterial colonies typical for Aeromonas salmonicida on tryptone soya agar (TSA) have been isolated and counted (from 3.0±0.6×102 to 3.5±0.5×105 c.f.u. g−1) from the internal organs of naturally infected (NI) and experimentally infected (EI) perch and sea trout. No significant differences in dark-brown bacterial counts were detected between EI perch and EI sea trout. The assessment and comparison of the alterations of the biological parameters of EI European perch and sea trout with bacterium Aeromonas salmonicida subsp. salmonicida with naturally infected perch were conducted. No mortality was recorded in groups of EI perch and sea trout. Whereas, the mortality of NI perch (collected from the main sites of outbreak of disease) was observed from the second day of the experiments. Changes in morphophysiological parameters of EI perch and sea trout were similar. Different alterations in blood cell parameters of EI fish were observed, and the most noticeable was the decrease (P≤0.01) in white blood cell count (WBC) of EI perch and sea trout. Based on these results it can be deduced that there is infection transmission of bacterium A. salmonicida from European perch via water to other fish species. 相似文献
11.
Periostin (postn) is a secreted, extracellular matrix protein containing an EMI domain as well as four fasciclin I-like (Fas1) domains. Postn protein functions in cell adhesion, cell mobility, cell proliferation and gene regulation. Earlier
studies have shown that postn is involved in different developmental processes such as somitogenesis, cardiogenesis and bone
formation. Intriguingly, postn seems to be a very good candidate to establish novel therapies against cancer and chronic heart
defects. Here we describe for the first time the spatio-temporal expression profile of postn during early development of Xenopus laevis. By semi-quantitative RT-PCR approaches, we demonstrate that postn is maternally expressed. Zygotic expression starts during early gastrulation and increases until stage 40. Whole mount in
situ hybridization experiments revealed that postn is detectable in somites, the sensory layer of the epidermis, the roof plate, the notochord, the heart, migrating neural
crest cells, cranial ganglia and forming cranial cartilage structures. Our results implicate a role of postn during Xenopus embryogenesis and represent a good starting point for future functional analyses. 相似文献
12.
Yanmei Zhang Fei Li Dongchang Sun Jiangdong Liu Na Liu Qixing Yu 《Molecular biology reports》2011,38(1):275-282
R-spondin1 (RSPO1) is a potential female-determining gene in human (Homo sapiens) and mouse (Mus musculus). Its differential expression in these mammals is correlated with signaling for sex determination. As a way of studying sex
determination in fish we cloned and analyzed a RSPO1 gene in zebrafish (Danio rerio). Using real-time PCR, we observed that RSPO1 is expressed more strongly in ovaries than in testes, suggesting that RSPO1 may have a role in gonad differentiation. High RSPO1 expression was detected in some non-gonadal organs like muscle and kidneys. In situ hybridization results demonstrate that
RSPO1 is expressed in premature germ cells, in oogonia and primary oocytes in ovaries and in spermatogonia and spermatocytes in
testes. It is also expressed in gonad somatic cells during gonadal development: in granulosa cells and theca cells of early
and late cortical-alveolar stage follicles in ovaries, and in Leydig cells in testes. This differential expression may indicate
that RSPO1 has a role(s) in zebrafish gonad development and differentiation. By fusing zebrafish RSPO1 with a green fluorescent protein gene, we found that RSPO1 is located in the cytosol and Golgi apparatus but not the nucleus
of fish epithelioma papulosum cyprinid (EPC) cells. These preliminary findings suggest some aspects of RSPO1 like differential
expression linked to sex determination may be conserved in fish while other aspects like subcellular localization differ from
the mammalian RSPO1. 相似文献
13.
Verleih M Rebl A Köllner B Korytář T Anders E Wimmers K Goldammer T 《Molecular biology reports》2012,39(4):4291-4300
14.
M. N. Melnikova S. D. Pavlov A. A. Kolesnikov N. B. Petrov 《Russian Journal of Genetics》2010,46(6):699-704
Using AP-PCR, the genome of Kamchatka mykiss (Parasalmo (O.) mykiss) was examined. Polymorphic fragments, implying geographic differences among the samples, were selected, cloned, and sequenced.
Based on these sequences, longer, specific SCAR primers were selected and constructed. Using the BLAST software program, the
sequences were analyzed for analogy to those from the GenBank database. It seemed likely that all sequences obtained belonged
to earlier unexamined repeated sequences, variable in the populations of the species of interest. A total of seven SCAR markers,
characterized by population-significant variability of the DNA products in Kamchatka geographic group of rainbow trout were
constructed. These markers can be used for further investigation of the species Parasalmo (O.) mykiss. The SCAR marker sequences were deposited in GenBank under the accession numbers EU805500 to EU805506. 相似文献
15.
Background
Trigeminal nerves consist of ophthalmic, maxillary, and mandibular branches that project to distinct regions of the facial epidermis. In Xenopus embryos, the mandibular branch of the trigeminal nerve extends toward and innervates the cement gland in the anterior facial epithelium. The cement gland has previously been proposed to provide a short-range chemoattractive signal to promote target innervation by mandibular trigeminal axons. Brain derived neurotrophic factor, BDNF is known to stimulate axon outgrowth and branching. The goal of this study is to determine whether BDNF functions as the proposed target recognition signal in the Xenopus cement gland. 相似文献16.
Uddin N Hoessli DC Butt A Kaleem A Iqbal Z Afzal I Muhammad Hammad Zamani Z Shakoori AR 《Molecular biology reports》2012,39(4):4663-4672
The complex life cycle of plasmodial parasites makes the selection of a single subunit protein a less than optimal strategy
to generate an efficient vaccinal protection against malaria. Moreover, the full protection afforded by malarial proteins
carried by intact parasites implies that immune responses against different antigens expressed in different phases of the
cycle are required, but also suggests that native malarial antigens are presented to the host immune system in a manner that
recombinant proteins do not achieve. The malarial apical membrane antigen 1 (AMA1) represents a suitable vaccine candidate
because AMA1 is expressed on sporozoites and merozoites and allows them to invade hepatocytes and erythrocytes, respectively.
Anti-AMA1 antibodies and cytotoxic T-cells are therefore expected to interfere both with the primary invasion of hepatocytes
by sporozoites and with the later propagation of merozoites in erythrocytes, and thus efficiently counteract parasite development
in its human host. AMA1 bears potential glycosylation sites and the human erythrocytic O-linked N-acetylglucosamine transferase (OGT) could glycosylate AMA1 through combinatorial metabolism. This hypothesis was tested in silico by developing binding models of AMA1 with human OGT complexed with UDP-GlcNc, and followed by the binding of O-GlcNAc with the hydroxyl group of AMA1 serine and threonine residues. Our results suggests that AMA1 shows potential for
glycosylation at Thr517 and Ser498 and that O-GlcNAc AMA1 may constitute a conformationally more appropriate antigen for developing a protective anti-malarial immune response. 相似文献
17.
Sexually matured rainbow trout, Oncorhynchus mykiss, were experimentally infected with the pathogenic Cryptobia salmositica. Spawning female trout were more susceptible to cryptobiosis than sexually mature males. Most infected females (seven of nine)
with eggs died before or shortly after spawning while all (nine) infected males survived the disease. Also, none of the uninfected
females died. Males initially increased milt production and sperm concentration; however semen production declined as the
disease progressed. Sperm from infected males fertilized more eggs than those from non-infected males. No differences in weight
and survival were observed between progeny of infected and uninfected males. 相似文献
18.
19.
Zilong Wang Xingfu Zha Ningjia He Zhonghuai Xiang Qingyou Xia 《Molecular biology reports》2010,37(5):2525-2531
RBP1 is an important splicing factor involved in alternative splicing of the pre-mRNA of Drosophila sex-determining gene dsx. In this work, the Bombyx mori homologue of the rbp1 gene, Bmrbp1, was cloned. The pre-mRNA of Bmrbp1 gene is alternatively spliced to produce four mature mRNAs, named Bmrbp1-PA, Bmrbp1-PB, Bmrbp1-PC and Bmrbp1-PD, with nucleotide lengths of 799 nt, 1,316 nt, 894 nt and 724 nt, coding for 142 aa, 159 aa, 91 aa and 117 aa, respectively.
BmRBP1-PA and BmRBP1-PD contain a N terminal RNA recognization motif (RRM) and a C terminal arginine/serine-rich domain, while
BmRBP1-PB and BmRBP1-PC only share a RRM. Amino acid sequence alignments showed that BmRBP1 is conserved with its homologues
in other insects and with other SR family proteins. The RT-PCR showed that Bmrbp1-PA was strongly expressed in all examined tissues and development stages, but Bmrbp1-PB was weakly expressed in these tissues and stages. The expression of both Bmrbp1-PA and Bmrbp1-PB showed no obvious sex difference. While the Bmrbp1-PC and Bmrbp1-PD were beyond detection by RT-PCR very likely due to their tissue/stage specificity. These results suggested that Bmrbp1 should be a member of SR family splicing factors, whether it is involved in the sex-specific splicing of Bmdsx pre-mRNA needs further research. 相似文献
20.
The maT clade of transposons is a group of transposable elements intermediate in sequence and predicted protein structure to mariner and Tc transposons, with a distribution thus far limited to a few invertebrate species. We present evidence, based on searches of publicly available databases, that the nematode Caenorhabditis briggsae has several maT-like transposons, which we have designated as CbmaT elements, dispersed throughout its genome. We also describe two additional transposon sequences that probably share their evolutionary history with the CbmaT transposons. One resembles a fold back variant of a CbmaT element, with long (380-bp) inverted terminal repeats (ITRs) that show a high degree (71%) of identity to CbmaT1. The other, which shares only the 26-bp ITR sequences with one of the CbmaT variants, is present in eight nearly identical copies, but does not have a transposase gene and may therefore be cross mobilised by a CbmaT transposase. Using PCR-based mobility assays, we show that CbmaT1 transposons are capable of excising from the C. briggsae genome. CbmaT1 excised approximately 500 times less frequently than Tcb1 in the reference strain AF16, but both CbmaT1 and Tcb1 excised at extremely high frequencies in the HK105 strain. The HK105 strain also exhibited a high frequency of spontaneous induction of unc-22 mutants, suggesting that it may be a mutator strain of C. briggsae. 相似文献