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201.
Masashi Yamada Toshihiko Ikeuchi Saburo Aimoto Dr. Hiroshi Hatanaka 《Neurochemical research》1996,21(7):815-822
PC12h-R cell, a subclone of PC12 cells, exhibited a neuron-like phenotype, including neurite outgrowth and increased acetylcholinesterase
activity, in response to epidermal growth factor (EGF) as well as nerve growth factor (NGF). We examined the mechanism by
which EGF induced the neuronal differentiation in PC12h-R cells. The EGF-induced neuronal differentiation of PC12h-R cells
was not blocked by K252a, whereas that induced by NGF was. EGF induced sustained tyrosine phosphorylation of the EGF receptor
in PC12h-R cells, but not in the parent PC12h cells, which do not show neuronal differentiation in response to EGF. In addition,
the rate of EGF-induced down-regulation of the EGF receptor in PC12h-R cells was decreased compared with that in PC12h cells.
Furthermore, we found that the duration of EGF-induced tyrosine phosphorylation of the EGF receptor in PC12h-R cells was similar
to that of NGF-induced tyrosine phosphorylation of p140
trkA in PC12h cells. The EGF-induced phosphorylation of the EGF receptor in PC12h cells was less sustained than that of p140
trkA by NGF in PC12h cells. These findings suggested that the EGF-induced neuronal differentiation of PC12h-R cells is due to
the sustained activation of the EGF receptor, resulting from the decreased down-regulation of the EGF receptor and that the
duration of the receptor tyrosine kinase activity determines the cellular responses of PC12 cells. We concluded that sustained
activation of the receptor tyrosine kinase induces neuronal differentiation, although transient activation promotes proliferation
of PC12 cells.
Special issue dedicated to Dr. Hans Thoenen. 相似文献
202.
Susumu Kimura 《Microbiology and immunology》1996,40(9):645-650
Reactivation of herpes simplex virus type 1 (HSV-1) occurred rapidly in cells of latently infected adult mouse trigeminal ganglia which were cultured in serum-free medium in the presence of sufficient nerve growth factor (NGF). However, HSV-1 reactivation was delayed significantly in ganglionic cultures in the absence of exogenous NGF or in cultures treated with 2-aminopurine in the presence of NGF. The delayed viral reactivation in ganglionic cultures without NGF was accelerated by treatment with phorbol myristate acetate or dibutyryl cyclic AMP. Culture conditions which affected HSV-1 reactivation did not affect replication of HSV-1 in normal ganglionic cultures. 相似文献
203.
204.
Yeon-Jeong Kim Jong-Hoon Park Koung-Sook Kim Ji-Eun Chang Jeong Heon Ko Myung-Hee Kim Dong-Hyo Chung Tae-Wha Chung In-Seong Choe Young-Choon Lee Cheorl-Ho Kim 《Gene》1996,170(2):281-283
We have isolated and characterized the immediate (1651 bp) 5′-flanking region of the gene (GnT-III) encoding N-acetylglucosaminyltransferase III (GnT-III) from a human placental genomic library. Analysis of promoter elements shows a similarity to the 5′-flanking region of murine 1,4-galactosyltransferase. The sequence lacks obvious TATA elements and CCAAT boxes; however, putative regulatory sites, including 2 potential cAMP-response regulatory elements (CRE), 11 insulin-response element consensus sequences (IRE), 7 potential AP-2-binding sites, 2 SP1 consensus sequences (GC boxes) and 2 sequences similar to the half-palindromic glucocorticoid-responsive element (GRE), are present. 相似文献
205.
超结瘤大豆(Glycine m ax (L.) Merr.) nts 382 和不结瘤大豆Nod 49 的叶和根组织水提取物经Sephadex G25 过滤、洗脱,再根据洗脱物对硝酸还原酶(NR)活性的影响可划分为4 个组分(fraction)样品,即nts 382(Nod 49) F1、nts 382(Nod 49) F2、nts 382(Nod 49) F3 和nts 382(Nod 49) F4。其中, nts382 F2 和F4 抑制NR 活性作用在接种USDA110 后明显下降, 但接种的nts 382 F2 却能提高大豆Bragg 的结瘤数达一倍, 而接种的nts 382 F3 和F4 的作用不明显。NR 活性抑制因子不是刺激结瘤的因子, 刺激结瘤的因子主要分布在接种的nts382 F2 部分中。与这一现象相反, Nod 49 F2 和F4 抑制NR活性的作用在接种后更强, 且也抑制大豆nts 382 的结瘤, 其中Nod 49 F4 抑制结瘤的作用基本不能逆转。抑制结瘤因子主要分布在接过种的Nod 49 F4 部分中 相似文献
206.
细胞外Ca^2+内流入胞质的机制 总被引:11,自引:0,他引:11
细胞外Ca^2+主要是通过塌压依赖性Ca^2+通道和钙池耗竭依赖性Ca^2+通道而内流的。前者主要见于电兴奋细胞,这一过程比较清楚;后者主要见非兴奋细胞,情况远较复杂:外来信号激活内贮钙池,钙池在释放Ca^2+同时通过目前尚不清楚的途径将直接或间接传至质膜Ca^2+通道,而诱发Ca^2+内流。 相似文献
207.
Paracrine functions of the coronary vascular endothelium 总被引:5,自引:0,他引:5
Ingrid Fleming Johann Bauersachs Rudi Busse 《Molecular and cellular biochemistry》1996,157(1-2):137-145
208.
The life cycle of the red alga Porphyra purpurea alternates between two morphologically distinct phases: a shell-boring, filamentous sporophyte and a free-living, foliose gametophyte. From a subtracted cDNA library enriched for sporophyte-specific sequences, we isolated a cDNA encoding an unusual elongation factor 1 (EF-1) that is expressed only in the sporophyte. A second EF-1 gene that is expressed equally in the sporophyte and the gametophyte was isolated from a genomic library. These are the only EF-1 genes detectable in P. purpurea. The constitutively expressed gene encodes and EF-1 very similar to those of most eukaryotes. However, the sporophyte-specific EF-1 is one of the most divergent yet described, with nine insertions or deletions ranging in size from 1 to 26 amino acids. This is the first report of a developmental stage-specific EF-1 outside of the animal kingdom and suggests a fundamental role for EF-1 in the developmental process. 相似文献
209.
A novel type of DNA-binding protein interacts with a conserved sequence in an early nodulin ENOD12 promoter 总被引:3,自引:0,他引:3
210.
Tetrapolar fungal mating types: Sexes by the thousands 总被引:6,自引:1,他引:5
Erika Kothe 《FEMS microbiology reviews》1996,18(1):65-87