2-5A trimer [5'-monophosphoryladenylyl(2'-5')adenylyl(2'-5')adenosine] activates RNase L. While the 5'-terminal and 2'-terminal adenosine N(6)-amino groups play a key role in binding to and activation of RNase L, the exocyclic amino function of the second adenylate (from the 5'-terminus) plays a relatively minor role in 2-5A's biological activity. To probe the available space proximal to the amino function of the central adenylate of 2-5A trimer during binding to RNase L, a variety of substituents were placed at that position. To accomplish this, the convertible building block 5'-O-dimethoxytrityl-3'-O-(tert-butyldimethylsilyl)-6-(2,4-dinitrophenyl)thioinosine 2'-(2-cyanoethylN,N-diisopropylphosphoramidite) was prepared as a synthon to introduce 6-(2,4-dinitrophenyl)thioinosine into the middle position of the 2-5A trimer during automated synthesis. Post-synthetic treatment with aqueous amines transformed the (2,4-dinitrophenyl)thioinosine into N(6)-substituted adenosines. Assays of these modified trimers for their ability to bind and activate RNase L showed that activation activity could be retained, albeit with some sacrifice compared to unmodified p5'A2'p5'A2'p5'A. Thus, the spatial domain about this N(6)-amino function could be available for modifications to enhance the biological potency of 2-5A analogues and to ligate 2-5A to targeting vehicles such as antisense molecules. 相似文献
Rab GTPases are Ras-like small molecular weight GTP binding proteins that are involved in various steps along the exocytic and endocytic pathways. Here we report that Rab39, a novel Rab protein, is a Golgi-associated protein involved in endocytosis of HeLa cells. Full-length cDNA of Rab39 contains 1251bp with an open reading frame (ORF) of 636bp, which is predicted to encode a 211 aa protein. By blast analysis of Rab39 cDNA and protein sequence with homologues, we find that Rab39 may be a short variant of Rab34. Rab39 contains conserved motifs involved in phosphate/guanosine binding and a microbody C-terminal targeting signal. RT-PCR analysis indicates that Rab39 is mainly detected in epithelial cell lines, and Northern blot analysis shows that Rab39 is expressed ubiquitously in human tissues. By using FITC-BSA as an endocytic tracer, we show that Rab39 can facilitate endocytosis in HeLa cells when expressed either transiently or stably. Confocal microscopy examination of Rab39 subcellular localization suggests that Rab39 is associated with Golgi-associated organelles. Our findings demonstrate that Rab39 is a novel Rab GTPase involved in cellular endocytosis. 相似文献
7-Chloro-4-nitrobenzofurazan (NBD-Cl) is a potent inhibitor of both types of monoamine oxidase (MAO). NBD-Cl competitively inhibited the oxidative deamination of kynuramine catalyzed by human placenta MAO-A, the oxidative deamination of benzylamine catalyzed by bovine liver MAO-B, the oxidative deamination of serotonin catalyzed by rat brain MAO-A, and the oxidative deamination of phenylethylamine catalyzed by rat brain MAO-B. In addition, a time-dependent inactivation of MAOs by NBD-Cl has been demonstrated upon incubation of the enzyme preparations with NBD-Cl at pH 9, but not at pH 7.5. The time-dependent inhibition of MAO by NBD-Cl could be prevented by the addition of 4-nitrophenyl azide, an active site-directed label of MAO, during incubation of the enzyme with NBD-Cl. On the basis of these findings, it is suggested that at pH 9, NBD-Cl modifies one (or more) essential lysine residue(s) in the active sites of the two types of MAO. 相似文献
Enhancer trapping has provided a powerful strategy for identifying novel genes and regulatory elements. In this study, we adopted an enhancer trap system, consisting of the GAL4/VP16-UAS elements with GUS as the reporter, to generate a trapping population of rice. Currently, 31 443 independent transformants were obtained from two cultivars using Agrobacterium-mediated T-DNA insertion. PCR tests and DNA blot hybridization showed that about 94% of the transformants contained T-DNA insertions. The transformants carried, on average, two copies of the T-DNA, and 42% of the transformants had single-copy insertions. Histochemical assays of approximately 1000 T0 plants revealed various patterns of the reporter gene expression, including expression in only one tissue, and simultaneously in two or more tissues. The expression pattern of the reporter gene in T1 families corresponded well with the T0 plants and segregated in a 3 : 1 Mendelian ratio in majority of the T1 families tested. The frequency of reporter gene expression in the enhancer trap lines was much higher than that in gene trap lines reported previously. Analysis of flanking sequences of T-DNA insertion sites from about 200 transformants showed that almost all the sequences had homology with the sequences in the rice genome databases. Morphologically conspicuous mutations were observed in about 7.5% of the 2679 T1 families that were field-tested, and segregation in more than one-third of the families fit the 3 : 1 ratio. It was concluded that GAL4/VP16-UAS elements provided a useful system for enhancer trap in rice. 相似文献
The H1N1 influenza virus causes acute respiratory tract infection, and its clinical symptoms are very similar to those of ordinary influenza. The disease develops rapidly. If the flu is not treated, complications such as pneumonia, respiratory failure, and multiple organ damage can occur, resulting in a high fatality rate. Influenza virus mutates rapidly. At present, there is no specific drug for H1N1, so it is an urgent need for clinical care to find new drugs to treat H1N1.
Materials and methods
The polysaccharide derived from Durvillaea Antarctica green algae has a certain antiviral effect. In this study, the results of CCK-8, apoptosis cycle detection, JC-1 and Western blotting proved that Duvira Antarctic polysaccharide (DAPP) has the ability to inhibit H1N1 infection.
Results
CCK-8 test showed that the DAPP with concentration at 32 μg/mL had no toxicity to MDCK cells. In addition, DAPP reduced cell apoptosis by inhibiting the ERK signaling pathway. Meanwhile, DAPP could increase the expression of STAT3 and significantly inhibited proinflammatory cytokines.
Conclusions
In summary, these results suggested that DAPP may be potential with the ability to resist the H1N1 influenza virus.
<正> In the present paper a new caprine, Sinocapra minor gen. et sp. nov. is erected on the basis of several horn cores. The type specimen was collected by the Sino-American Palaeontology Expedition from the Upper Pliocene, Mazegou Formation, of Yunzhu Subbasin, Yushe Basin, Shansi province in 1988. All the other ones referred to the new genus were described and identified by Teilhard de Chardin and Trassaert (1938, p. 53, fig. 46) as Antilope gen. et sp. indet. They also came from Zhaozhuang, Yunzhu Subbasin and it is likely that they might be gathered from the same Formation as the type specimen judging by the yellow sandy clay filling into the horn cores. Magnetostratigraphic studies by Prof. N. Opdyke of the Yunzhu Subbasin indicates that this stratigraphic interval only includes the Gauss one, approximately 3.4 to 2.47 Ma. Accounts of the biostratigraphy and dating of Yunzhu Subbasin are giyen by Dr. R. H. Tedford and Dr. Z. Qiu in another paper. 相似文献
Glypicans influence signaling pathways by regulating morphogen trafficking and reception. However, the underlying mechanisms in vertebrates are poorly understood. In zebrafish, Glypican 4 (Gpc4) is required for convergence and extension (C&E) of both the mesoderm and endoderm. Here, we show that transgenic expression of GFP-Gpc4 in the endoderm of gpc4 mutants rescued C&E defects in all germ layers. The rescue of mesoderm was likely mediated by Wnt5b and Wnt11f2 and depended on signaling filopodia rather than on cleavage of the Gpc4 GPI anchor. Gpc4 bound both Wnt5b and Wnt11f2 and regulated formation of the filopodia that transport Wnt5b and Wnt11f2 to neighboring cells. Moreover, this rescue was suppressed by blocking signaling filopodia that extend from endodermal cells. Thus, GFP-Gpc4–labeled protrusions that emanated from endodermal cells transported Wnt5b and Wnt11f2 to other germ layers, rescuing the C&E defects caused by a gpc4 deficiency. Our study reveals a new mechanism that could explain in vivo morphogen distribution involving Gpc4. 相似文献
Chronic pancreatitis (CP) is described as progressive inflammatory fibrosis of pancreas, accompanied with irreversible impaired endocrine and exocrine insufficiency. Pancreatic stellate cells (PSCs) are widely distributed in the stroma of the pancreas and PSCs activation has been shown as one of the leading causes for pancreatic fibrosis. Our previous study has revealed that autophagy is dramatically activated in CP tissues, which facilitates PSCs activation and pancreatic fibrosis. Long non-coding RNAs (LncRNAs) have been recognized as crucial regulators for fibrosis-related diseases. LncRNAs interact with RNA binding protein or construct competitive endogenous RNA (ceRNA) hypothesis which elicited the fibrotic processes. Until now, the effects of lncRNAs on PSCs activation and pancreatic fibrosis have not been clearly explored. In this study, a novel lncRNA named Lnc-PFAR was found highly expressed in mouse and human CP tissues. Our data revealed that Lnc-PFAR facilitates PSCs activation and pancreatic fibrosis via RB1CC1-induced autophagy. Lnc-PFAR reduces miR-141 expression by suppressing pre-miR-141 maturation, which eventually upregulates the RB1CC1 and fibrosis-related indicators expression. Meanwhile, Lnc-PFAR enhanced PSCs activation and pancreatic fibrosis through trigging autophagy. Our study interrogates a novel lncRNA-induced mechanism in promoting the development of pancreatic fibrosis, and Lnc-PFAR is suggested to be a prospective therapeutic target in clinical scenarios.Subject terms: RNAi, Diagnostic markers, Chronic pancreatitis相似文献