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81.
82.
Octopamine is a major monoamine in invertebrates and affects many physiological processes ranging from energy metabolism to complex behaviors. Octopamine binds to receptors located on various cell types and activates distinct signal transduction pathways to produce these diverse effects. We previously identified one of the Drosophila octopamine receptors named OAMB that produces increases in cAMP and intracellular Ca2+ upon ligand binding. It is expressed at high levels in the brain. To explore OAMB's physiological roles, we generated deletions in the OAMB locus. The resultant oamb mutants were viable without gross anatomical defects. The oamb females displayed normal courtship and copulation; however, they were impaired in ovulation with many mature eggs retained in their ovaries. RT-PCR, in situ hybridization, and expression of a reporter gene revealed that OAMB was also expressed in the thoracicoabdominal ganglion, the female reproductive system, and mature eggs in the ovary. Moreover, analysis of various alleles pinpointed the requirement for OAMB in the body, but not in the brain, for female fecundity. The novel expression pattern of OAMB and its genetic resource described in this study will help advance our understanding on how the neuromodulatory or endocrine system controls reproductive physiology and behavior. 相似文献
83.
The CD99 signal enhances Fas-mediated apoptosis in the human leukemic cell line, Jurkat 总被引:1,自引:0,他引:1
The CD99 antigen has been implicated in various cellular processes, including apoptosis in T cells. Previously, we reported two monoclonal antibodies that recognize different epitopes of the CD99 molecule, named DN16 and YG32. In this study, we investigated the role of each CD99 epitope in T cell apoptosis. Unlike the DN16 epitope, CD99 ligation via the YG32 epitope failed to induce T cell death. Surprisingly, however, the YG32 signal enhanced Fas-mediated apoptosis in Jurkat T cells. Augmentation of Fas-mediated apoptosis by YG32 ligation was inhibited by treatment with either of the caspase inhibitors z-VAD-fmk or z-IETD-fmk, and YG32 ligation appeared to induce Fas oligomerization. These results suggest that each CD99 epitope plays a distinct role in T cell biology, especially in T cell apoptosis. 相似文献
84.
Oh SC Nam SY Kwon HC Kim CM Seo JS Seong RH Jang YJ Chung YH Chung HY 《Molecules and cells》2001,11(2):192-197
We generated new fusion genes carrying positive- and negative-selection markers, and a reporter gene in a single reading frame. The new genes were constructed by sequentially linking the coding sequences of drug-resistance genes (hygro, or puro), a green fluorescence protein (GFP) gene (gfp), and the thymidine kinase gene (tk). The new synthetic genes (hygro/gfp/tk and puro/ gfp/tk) were inserted into retroviral vectors to test their usefulness as selective markers and reporters. The genes were functional in a positive selection in the presence of hygromycin (hygro/gfp/tk) or puromycin (puro/gfp/ tk). In addition, cells expressing the new fusion genes were clearly identifiable by their green fluorescence emitted from GFP. At the same time, these cells were sensitive to a gancyclovir treatment, allowing efficient removal of the transduced cells. The presently described synthetic genes will be valuable tools in both gene therapy and basic gene transfer studies, where positive selection of the transduced cells, monitoring gene expression, and negative selection of the transduced cells are simultaneously required. 相似文献
85.
86.
The enhanced reactivity of endogenous biotin-like molecules by antigen retrieval procedures and signal amplification with tyramine 总被引:2,自引:0,他引:2
Kim SH Jung KC Shin YK Lee KM Park YS Choi YL Oh KI Kim MK Chung DH Son HG Park SH 《The Histochemical journal》2002,34(3-4):97-103
In diagnostic pathology and immunocytochemical research, immunohistochemical techniques using the streptavidin–biotin–peroxidase system have played an extremely valuable role. This system, based on the high affinity of streptavidin for biotin, may, however, provoke false positive results because of endogenous streptavidin-binding sites in human tissues. With the advent of the antigen retrieval procedure and signal amplification method, this problem can be serious enough to cause mistakes in interpreting immunohistochemical staining results. Therefore, we examined the distribution of endogenous biotin-like molecules in various human tissues and the influence of various antigen retrieval procedures with or without signal amplification using biotinylated tyramine to reveal these biotin-like activities. We observed that endogenous biotin-like molecules were present in a wide range of tissues, and their activity was markedly enhanced by employing antigen retrieval procedures or signal amplification. Furthermore, the extent to which the activity of endogenous biotin-like activities was enhanced depended on the kinds of antigen retrieval procedures and signal amplification employed. Pressure cooking and tyramine amplification with microwave heating showed the highest activities. These results show that the antigen retrieval procedures and signal amplification with tyramine can enhance the activity of endogenous biotin or biotin-like molecules as well as antigenicity, which can be a pitfall in the interpretation of immunohistochemical data. 相似文献
87.
Human brain nucleoside diphosphate kinase activity is decreased in Alzheimer's disease and Down syndrome 总被引:4,自引:0,他引:4
Kim SH Fountoulakis M Cairns NJ Lubec G 《Biochemical and biophysical research communications》2002,296(4):970-975
In brain, nucleoside diphosphate kinase (NDPK) and its coding gene, nm23, have been implicated to modulate neuronal cell proliferation, differentiation, and neurite outgrowth. However, a role of NDPK in neurodegenerative diseases has not been reported yet. Using proteomics techniques, we evaluated the protein levels of NDPK-A in seven brain regions from patients with Alzheimer's disease (AD) and Down syndrome (DS) showing AD-like neuropathology. NDPK-A was significantly decreased in brain regions (frontal, occipital, and parietal cortices) of both disorders. Due to the limitation of brain samples, the activity of NDPK was measured in three brain regions (frontal cortex, temporal cortex, and cerebellum). The specific activity of NDPK was significantly decreased in AD (frontal cortex) and DS (frontal and temporal cortices). Since NDPK-B could also drive the activity of NDPK, protein expression levels of both NDPK-A and NDPK-B were studied in frontal cortex by Western blot analysis. NDPK-A was significantly decreased in AD, which was consistent with the results of proteomics. However, NDPK-A was slightly decreased in DS and protein expression levels of NDPK-B in both DS and AD were moderately decreased, without reaching statistical significance. We propose that oxidative modification of NDPK could lead to the decreased activity of NDPK and, subsequently, influence several neuronal functions in neurodegenerative diseases as multifunctional enzyme through several mechanisms. 相似文献
88.
We previously demonstrated the presence of three distinct types of the gonadotropin-releasing hormone receptor (GnRHR) in a bullfrog (denoted bfGnRHR-1, bfGnRHR-2, and bfGnRHR-3). The bfGnRHRs exhibited differential tissue distribution and ligand selectivity. In the present study, we demonstrated the desensitization and internalization kinetics of these receptors in both transiently-transfected HEK293 cells and retrovirus-mediated stable cells. The time-course accumulation of the inositol phosphate in response to GnRH revealed that bfGnRHR-1 and -2 were rapidly desensitized, whereas bfGnRHR-3 was slowly desensitized. A comparison of the internalization kinetics revealed the most rapid rate and highest extent of internalization of bfGnRHR-2 among the three receptors. Interestingly, the mechanisms that underlie the receptor internalization appear to differ from each other. Internalization of bfGnRHR-1 was dependent on both dynamin and beta-arrestin, whereas those of bfGnRHR-2 and -3 were dependent on dynamin, but not on arrestin. These results, therefore, suggest that differential regulatory mechanisms for desensitization and internalization of the GnRHR are involved in diverse cellular and physiological responses to GnRH stimulation. 相似文献
89.
Suh YH Kim MK Shin YK Kim SH Oh KI Gil M Kim MK Choi YL Jung KC Lee KM Lee IS Park SH 《Molecules and cells》2002,13(2):237-244
Hodgkin's disease (HD) is a lymphoid neoplasm characterized by a low frequency of malignant giant tumor cells, known as Hodgkin's and Reed-Sternberg (HRS) cells. Sequence analysis of the immunoglobulin heavy chain hypervariable region (IgH V) genes of HRS cells revealed multiple nucleotide substitutions, indicating somatic mutations, and suggested that HRS cells originate from germinal center B cells or their progeny. We previously reported that CD99-antisense transfected B cell lines led to the generation of cells with a HRS phenotype. Because it is considered that HRS cells in HD carry somatic mutations of the IgH genes, we assume that somatic mutation may take place in the IgH genes of HRS-like cells which do not express CD99. Here we report that CD99 downregulated BJAB cell line has several mutations in IgH V genes. The frequency of mutation was 5.2 x 10(-4) mut.bp(-1) out of total sequenced cell clones. On the contrary, control vector transfected BJAB cell line or CD99 downregulated IM9 cell line did not show any mutations on single strand conformational polymorphism (SSCP) and sequence analysis. We expect that the analysis of the mutation pattern of the CD99-deficient BJAB cell line might be the basis for the understanding of the molecular and cellular mechanism that regulate somatic mutation and B cell selection. 相似文献
90.
A polymorphism in the toll-like receptor 2 is associated with IL-12 production from monocyte in lepromatous leprosy 总被引:9,自引:0,他引:9
Toll-like receptor 2 (TLR2) is critical in the immune response to mycobacterial infections, and the mutations in the TLR2 have been shown to confer the susceptibility to infection with mycobacteria. We previously reported the detection of TLR2 Arg677Trp mutation in lepromatous leprosy. Here, the events triggered by TLR2 in response to cell lysate of Mycobacterium leprae(MLL), the causative agent of leprosy, were investigated. Upon stimulation with MLL, monocytes produced TNF-alpha and Interleukin-12 (IL-12), which play a role in the innate immune response to infection. Anti-TLR2 mAb blocked greater than 50% of the MLL-induced production of IL-12. We also performed the functional study on TLR2 by measurement of IL-12 production in serum and monocytes from leprosy patients with TLR2 mutation (Arg677Trp). The monocytes obtained from patients with the TLR2 mutation, in comparison to the wild-type TLR2, is significantly less responsive to MLL. It was also confirmed that patients with TLR2 mutation showed significantly lower serum levels of IL-12, in comparing with TLR2 wild-type. Our results reveal that innate immune response of monocytes against M. lepraeis mediated by TLR2, and suggest that the mutation in the intracellular domain of TLR2 gene is associated with IL-12 production in lepromatous leprosy. 相似文献