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811.
Tsukiyama-Kohara K Toné S Maruyama I Inoue K Katsume A Nuriya H Ohmori H Ohkawa J Taira K Hoshikawa Y Shibasaki F Reth M Minatogawa Y Kohara M 《The Journal of biological chemistry》2004,279(15):14531-14541
Hepatitis C virus (HCV) causes persistent infection in hepatocytes, and this infection is, in turn, strongly associated with the development of hepatocellular carcinoma. To clarify the mechanisms underlying these effects, we established a Cre/loxP conditional expression system for the precisely self-trimmed HCV genome in human liver cells. Passage of hepatocytes expressing replicable full-length HCV (HCR6-Rz) RNA caused up-regulation of anchorage-independent growth after 44 days. In contrast, hepatocytes expressing HCV structural, nonstructural, or all viral proteins showed no significant changes after passage for 44 days. Only cells expressing HCR6-Rz passaged for 44 days displayed acceleration of CDK activity, hyperphosphorylation of Rb, and E2F activation. These results demonstrate that full genome HCV expression up-regulates the CDK-Rb-E2F pathway much more effectively than HCV proteins during passage. 相似文献
812.
Peptides derived from the post-translational processing of preprosodefrin were isolated from an extract of the abdominal glands of male red-bellied newts Cynops pyrrhogaster obtained 5 months prior to the onset of the breeding season. Structural characterization of the peptides showed that the pheromone sodefrin (SIPSKDALLK) is stored in a biologically inactive COOH-terminally extended form (SIPSKDALLKISA). It follows, therefore, that the activation of a protease that cleaves at a Lys-Ile bond to generate the active pheromone must occur by the time of onset of reproductive behavior. Additional peptides (representing preprosodefrin-(146-175)-peptide and preprosodefrin-(159-173)-peptide), that are derived from the precursor by cleavage at monobasic and dibasic processing sites, were also purified from the extract. The isolation of paralogs of these peptides, including an inactive COOH-terminally extended form of [Asn10]sodefrin, provides evidence for the expression of multiple genes encoding preprosodefrin. PCR products derived from total RNAs from the abdominal gland of individual newts collected from three different regions of Japan were analyzed. The data confirm the existence of multiple genes encoding sodefrin and its variants whose expression varied according to the individuals and the regions. However, genes encoding sodefrin were found to be expressed in all the specimens sampled. 相似文献
813.
From the leaves of Lasianthus fordii, three megastigmane glucosides, lasianthionosides A, B and C, were isolated together with the known iridoid glucoside, asperuloside, deacetylasperuloside and methyl deacetyl-asperulosidate, and a megastigmane glucoside, citroside A. The structures have been elucidated based on spectroscopic analyses and/or X-ray crystallographic analysis. 相似文献
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Urushihara H Morio T Saito T Kohara Y Koriki E Ochiai H Maeda M Williams JG Takeuchi I Tanaka Y 《Nucleic acids research》2004,32(5):1647-1653
Dictyostelium is a favored model for studying problems in cell and developmental biology. To comprehend the genetic potential and networks that direct growth and multicellular development, we are performing a large-scale analysis of Dictyostelium cDNAs. Here, we newly determine 7720 nucleotide sequences of cDNAs from the multicellular, slug stage (S) and 10 439 from the unicellular, vegetative stage (V). The combined 26 954 redundant ESTs were computer assembled using the PHRAP program to yield 5381 independent sequences. These 5381 predicted genes represent about half of the estimated coding potential of the organism. One-third of them were classified into 12 functional categories. Although the overall classification patterns of the V and S libraries were very similar, stage-specific genes exist in every category. The majority of V-specific genes function in some aspect of protein translation, while such genes are in a minority in the S-specific and common populations. Instead, genes for signal transduction and multicellular organization are enriched in the population of S-specific genes. Genes encoding the enzymes of basic metabolism are mainly found in the common gene population. These results therefore suggest major differences between growing and developing Dictyostelium cells in the nature of the genes transcribed. 相似文献
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Kawase Y Iwata T Toyoda Y Wakayama T Yanagimachi R Suzuki H 《Molecular reproduction and development》2001,60(1):74-78
We compared the results of intracytoplasmic sperm injection (ICSI) that leads to full term development of hybrid (B6C3F1 and B6D2F1) and inbred (C57BL/6) mouse embryos. Although fertilization and pre-implantation development of C57BL/6 eggs were similar to those of F1 hybrid eggs, post-implantation development of the embryos from C57BL/6 females was significantly poorer than those of the eggs from hybrid females. Reciprocal crosses of C57BL/6 and B6C3F1 gametes revealed that the low rate of post-implantation development of C57BL/6 embryos was due to oocyte factor(s), rather than the sperm factor. 相似文献