Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0033036 (APC)
 10,214 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A novel shuttle vector, pBH140, has been constructed that allows stable maintenance of large genomic inserts as human artificial episomal chromosomes (HAECs) in mammalian cells. The vector, essentially a hybrid BAC-HAEC, contains an F-based replication system as in a bacterial artificial chromosome (BAC) and the Epstein-Barr virus (EBV) latent origin of replication system, oriP, for replication in human cells. A 185-kb DNA insert containing the entire human beta-globin locus, including its locus control region (LCR), was retrofitted into this vector. The resulting beta-globin BAC-HAEC clone, p148BH, was transfected into human cells and analyzed for episomal maintenance and expression of the beta-globin gene. FISH revealed an association of the vector with different human chromosomes but no integration. The beta-globin BAC-HAECs were present at an average copy number of 11-15 per nucleus in the stably transformed human cells. After 1 year of continuous in vitro cultivation, the HAECs persisted as structurally intact 200-kb episomes. While no beta-globin transcription could be detected in the parental D98/Raji cells, correctly spliced RT-PCR products were produced at significant levels in long-term cultures of the BAC-HAEC-transduced cells. The wide availability of BAC and PAC libraries, the ease in manipulating cloned DNA in bacteria, and the episomal stability of the pBH140 vector make this system ideal for studies on gene expression and other genomic functions in human cells. The potential significance of large, functionally active episomes for gene therapy is discussed.
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PMID:A system for shuttling 200-kb BAC/PAC clones into human cells: stable extrachromosomal persistence and long-term ectopic gene activation. 974 25

Recently, a newly identified human HERV-K18 like endogenous retrovirus (IDDMK(1,2)22) has been associated to the etiology of type I diabetes (IDDM). Although the exact mechanism remains unclear, it was postulated that the 3' end ORF product of the env gene of IDDMK(1,2)22 would trigger a V beta 7-specific human T cell expansion leading to their infiltration in the pancreas of afflicted patients and to the autoimmune destruction of the insulin-producing beta cells. Since then, such superantigen (SAg)-like activity as well as the association between the IDDMK(1,2)22 virus and IDDM pathogenesis have been challenged. To further characterize functionally the putative IDDMK(1,2)22-encoded SAg, we have cloned from human DNA the identical 462bp ORF sequence originally described. The IDDMK(1,2)22 ORF fragment was transfected in the same human B cell line (Raji) originally used as APC to demonstrate the V beta 7 specificity. The immunostimulatory potential of IDDM ORF was tested on murine T cell hybridomas and compared to the well-characterized mouse mammary tumor virus Mtv7 SAg transfected in the same conditions. A panel of 16 T cell hybridomas encompassing 14 different V betas was analyzed. We have failed to detect IDDMK(1,2)22-induced IL-2 production from any of these hybridomas, even those bearing the murine V beta 1 mV beta 1, V beta 4 or V beta 10 TcR beta chains which are most closely related to the human V beta 7 (hV beta 7). Our results suggest that IDDMK(1,2)22 ORF is devoid of superantigenic activity as defined by classical criteria.
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PMID:Human endogenous retrovirus IDDMK(1,2)22 and mouse mammary tumor virus superantigens differ in their ability to stimulate murine T cell hybridomas. 1184 50

Engagement of the T cell with Ag on an APC results in a series of immediate signaling events emanating from the stimulation of the TCR. These events include the induced phosphorylation of a number of cellular proteins with a subsequent increase in intracellular calcium and the restructuring of the microtubule and actin cytoskeleton within the T cell. This restructuring of the cytoskeleton culminates in the polarization of the T cell's secretory apparatus toward the engaging APC, allowing the T cell to direct secretion of cytokines toward the appropriate APC. This polarization can be monitored by analyzing the position of the microtubule-organizing center (MTOC), as it moves toward the interface of the T cell and APC. The requirements for MTOC polarization were examined at a single-cell level by studying the interaction of a Jurkat cell line expressing a fluorescently labeled MTOC with Staphylococcal enterotoxin superantigen-bound Raji B cell line, which served as the APC. We found that repolarization of the MTOC substantially followed fluxes in calcium. We also used immobilized anti-TCR mAb and Jurkat signaling mutants, defective in TCR-induced calcium increases, to determine whether signaling components that are necessary for a calcium response also play a role in MTOC polarization. We found that zeta-associated protein-70 as well as its substrate adaptor proteins linker for activation of T cells and Src homology 2 domain-containing leukocyte protein-76 are required for MTOC polarization. Moreover, our studies revealed that a calcium-dependent event not requiring calcineurin or calcium/calmodulin-dependent kinase is required for TCR-induced polarization of the MTOC.
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PMID:Linker for activation of T cells, zeta-associated protein-70, and Src homology 2 domain-containing leukocyte protein-76 are required for TCR-induced microtubule-organizing center polarization. 1284 55

This study was aimed to investigate the efficiency of nested methylation specific polymerase chain reaction (nMS-PCR) for detecting the APC gene promoter methylation and to clarify the roles of methylation in genesis and development of hematologic malignancies, as well as to screen the hematologic malignant cell lines with hypermethylation of APC gene promoter to use as an ideal cell model for exploring the relationship between gen methylation and gene expression. The genome DNA of 10 cell lines modified with bisulfide was amplified and the methylation status of APC gene promoter was detected by using nMS-PCR. The results showed that the methylation of APC gene promoter was detected in Jurkat cells, while could not be detected in CA46, U266, Molt4, K562, HL-60, CEM, AKR, U937 and Raji cell lines. In conclusion, APC gene methylation in hematological malignant cell lines can be accurately detected by nMS-PCP method, which is simple method for detecting methylation status of various hematological malignant cell lines.
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PMID:[Detection of APC gene promoter methylation in hematological malignant cell lines by nested-methylation specific polymerase chain reaction]. 1969 37