New trap vectors (Ul and U2) have been developed to trap genes in murine embryonic stem (ES) cells. The polyA addition signal of the neomycin phosphotransferase II (neo) gene was removed from these vectors so that they needed to trap an endogenous polyA signal for expression of the neo gene. The frequency of gene-trap events of these vectors was about five times higher than with the vector containing the polyA signal, and only one copy of the trap vector was integrated in most cases. Four out of five 5'-flanking regions of the integrated vector in ES cell lines were found to be novel endogenous promoters, suggesting that this method is efficient for trapping genes in ES cells. In two cases analyzed, large deletions or rearrangements spanning more than 10 kb were found in the 3'-flanking region of the trap vector introduced by electroporation. This result suggests that phenotypes observed in homozygotes with a mutated allele could be due to the disruption of a gene adjacent to the trapped gene, but not of the trapped gene.One strategy for monitoring transcriptionally active regions of a genome invalves use of an enhancer trap, based on the fact that transcription of a reporter gene containing a minimum promoter is activated by cellular enhancers. In Drosophila, the enhancer trap strategy has been used successfully in large-scale screening of developmentally regulated genes (1, 2). The /J-galactosidase (lacZ) reporter gene provided a sensitive and easily assayable gene product to detect expression in whole embryos. A similar strategy was applied to mice, and transgenic mice carrying enhancer trap vectors were found to exhibit unique temporal and spatial patterns of lacZ expression (3, 4). To use this strategy effectively on a large scale in mice, lacZ reporter constructs were introduced into mouse embryonic stem (ES) cells. However, in mice the expression of a reporter gene is often influenced by the integration site, and an enhancer is sometimes located far from a coding region. These features make it difficult to identify and isolate the mouse endogenous gene. A second type of vector which was designed as a gene trap was developed to clone the promoter or exon sequences of the endogenous gene directly. The gene-trap vector contains a splice acceptor instead of a weak promoter in front of a lacZ gene (5). Thus, gene trap vectors are expected to generate spliced fusion transcripts between the reporter gene and the endogenous gene present at the site of integration (6, 7). In addition, all insertions of the gene trap vector may result in a mutation in the host
Anti-epiligrin cicatricial pemphigoid (AECP) is a chronic, mucous membrane-dominated, subepithelial blistering disease characterized by circulating anti-basement membrane zone auto-antibodies to laminin 5. Recent studies have shown that people with AECP have an increased relative risk for malignant tumours. In this report we describe two patients with AECP. In both cases, indirect immunofluorescence demonstrated circulating IgG anti-basement membrane auto-antibodies that bound to the dermal side of 1M NaCl split normal skin. Immunoblotting using laminin 5 purified from keratinocyte extract as a substrate showed that the IgG antibodies of patient 1 reacted with the 140-kDa beta3 subunit of laminin 5 and IgG antibodies of patient 2 reacted with the 165-kDa and 145-kDa alpha3 subunits. Patient 1 had prostate carcinoma and his blistering was resistant to therapy. Patient 2 had no detectable malignancy and treatment with doxycycline was successful.
Herein, we describe a rare case of giant malignant peripheral nerve sheath tumor of the head in a 38-year-old Japanese man. The tumor measured 210 mm at its largest diameter and was ulcerated, hemorrhagic, multilocular and non-mobile. It should be noted that the patient stubbornly refused to see a doctor for a long time, resulting in the extreme growth of the tumor. We suspect a psychological basis for this behavior. Dermatohistopathological findings of the biopsy indicated ancient schwannoma and total excision was therefore performed. However, after 4 months, the patient developed multiple metastases and died. Post-mortem skin biopsy revealed features of malignant peripheral nerve sheath tumor. We performed immunohistochemical studies on the primary and recurrent lesions and concluded that there was a difference in the expression of Ki67 and p16. We propose that the expressions of Ki67 and p16 should be checked for all lesions of peripheral nerve sheath tumor for distinguishing benign from malignant forms.
Detection of the COL1A1/PDGFB fusion transcript may be important for the diagnosis of DFSP. Furthermore, relative PDGFB gene quantification by real-time PCR may also provide a good diagnostic tool when other methods fail to give conclusive results.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.