Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.49 (reverse transcriptase)
 31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To examine whether proteases are possibly involved in cellular migration and/or spermiation when developing germ cells translocate across the seminiferous epithelium during spermatogenesis, in situ hybridization was used to localize messenger RNA (mRNA) transcripts of cathepsin L, D, and S in the epithelium at different stages of the spermatogenic cycle in the rat. Cathepsin L mRNA was found to localize almost exclusively near the basal lamina of the epithelium. At stages VI and VII of the cycle before spermiation, the signal of cathepsin L mRNA was so intense that it formed a complete dark precipitate near the basal lamina encircling the entire tubule. At stage VIII, the expression of cathepsin L was completely abolished, and no staining of cathepsin L mRNA was seen in the epithelium. The mRNA of cathepsin D and S was found near the basal lamina, a finding consistent with their localization in Sertoli cells and possibly primary spermatocytes in almost all stages, but peaked at stages VII-IX and VII-VIII of the cycle, respectively, at the time before and during spermiation. These results illustrate the possible involvement of these proteases in facilitating germ cell movement and spermiation. To examine whether germ cells express any of these cathepsin genes, spermatocytes with a purity of greater than 95% were isolated from 15-day-old rat testes by Percoll gradient centrifugation for reverse transcriptase-polymerase chain reaction. It was found that primary spermatocytes expressed multiple cathepsin genes, including cathepsin B, C, D, H, L, and S. Furthermore, the expression of cathepsin L by germ cells isolated from 15-day-old rats (largely spermatocytes and spermatogonia) can be stimulated by Sertoli cell-enriched culture medium in a dose-dependent manner, but not by germ cell-conditioned medium. These results reveal that germ cell function can be regulated by Sertoli cells. Moreover, these results suggest that germ cells may play an active role in the overall testicular protease expression. Also, we present evidence suggesting there is cross-talk between Sertoli and germ cells, since the expression of cathepsin L in each cell type is regulated by one another via either soluble factors or cell-cell contact.
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PMID:Evidence for cross-talk between Sertoli and germ cells using selected cathepsins as markers. 987 20

Thymidine phosphorylase (TP) has been implicated as a potent angiogenic factor and a prognostic factor in various human solid tumors. We investigated the expression of TP in a series of human astrocytic tumors using immunohistochemistry, enzyme-linked immunosorbent assay, and reverse transcriptase/polymerase chain reaction (RT-PCR) analysis. A total of 63 astrocytic tumors [27 glioblastomas (GBM), 19 anaplastic astrocytomas (AA), 17 low-grade astrocytomas (LGA)] and 5 normal brain tissues were immunohistochemically stained with antibodies to TP, vascular endothelial growth factor (VEGF), p53, MIB-1, and factor-VIII-related antigen. They were also evaluated for the degree of apoptosis by a ApopTag kit. Ten tumors (5 GBM, 2 AA, 3 LGA) and 3 normal brain tissues were evaluated for their expression of VEGF and TP by RT-PCR analysis. TP was constantly localized in the cytoplasm of astrocytic tumor cells, less intensely in the cytoplasm of vascular endothelial cells, but not in the normal brain. Some of the TP-positive cells were of macrophage origin, but most positive cells were the tumor cells themselves. Vascular density, MIB-1 positivity, p53 positivity, VEGF expression, and the apoptotic index were significantly higher in the TP-positive tumors than in TP-negative tumors. There was a significant correlation between TP and VEGF mRNA expression. In a limited number of glioblastoma cases, the apoptotic index was significantly higher in TP-positive glioblastomas than in TP-negative glioblastomas. In human astrocytic tumors, TP was expressed in the tumor, macrophage, and endothelial cells. TP was a potent angiogenic factor closely associated with cell proliferation and tumor apoptosis.
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PMID:Expression of the angiogenic factor thymidine phosphorylase in human astrocytic tumors. 1074 8

Nitric oxide (NO) is a simple and relatively unstable radical under physiological conditions. It is synthesized by three isoforms of NO synthase, that is neuronal, endothelial and inducible (iNOS) isoforms. In the present study, we investigated the distribution of iNOS with immunohistochemical methods in the mouse testis. The iNOS-immunoreactivity was detected on the basal region of the seminiferous tubules, where the cytoplasm of Sertoli cells was selectively immunolabeled. This immunoreactivity was observed by both immunofluorescent and immunoenzyme methods. Weak immunoreactivity was detected on the perinuclear cytoplasm of Sertoli cells throughout the seminiferous stages, whereas in stages I-VIII, it was remarkable on the processes of Sertoli cells surrounding the spermatogonia and early spermatocytes, and elongating into the lumina of seminiferous tubules. By reverse transcriptase-polymerase chain reaction, mRNA for iNOS was found to be expressed in the mouse testis. These results reveal that iNOS is consistently distributed at the front of the testicular environment.
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PMID:Expression and distribution of inducible nitric oxide synthase in mouse testis. 1261 3

In an effort to identify novel targets for the development of nonhormonal male contraceptives, genome-wide transcriptional profiling of the rat testis was performed. Specifically, enzymatically purified spermatogonia plus early spermatocyctes, pachytene spermatocytes, round spermatids, and Sertoli cells was analyzed along with microdissected rat seminiferous tubules at stages I, II-III, IV-V, VI, VIIa,b, VIIc,d, VIII, IX- XI, XII, XIII-XIV of the cycle of the seminiferous epithelium using RAE 230_2.0 microarrays. The combined analysis of these studies identified 16,971 expressed probe sets on the array. How these expression data, combined with additional bioinformatic data analysis and quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) analysis, led to the identification of 58 genes that have 1000-fold higher expression transcriptionally in the testis when compared to over 20 other nonreproductive tissues is described. The products of these genes may play important roles in testicular and/or sperm function, and further investigation on their utility as nonhormonal contraceptive targets is warranted. Moreover, these microarray data have been used to expedite the identification of a mutation in RIKEN cDNA 2410004F06 gene as likely being responsible for spermatogenic failure in a line of infertile mice generated by N-ethyl-N-nitrosourea (ENU) mutagenesis. The microarray data and the qRT-PCR data described are available in the Mammalian Reproductive Genetics database (http://mrg.genetics.washington.edu/).
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PMID:Identification of testis-specific male contraceptive targets: insights from transcriptional profiling of the cycle of the rat seminiferous epithelium and purified testicular cells. 1818 10

Sox11 is a high-mobility group (HMG)-containing transcription factor that is significantly elevated in peripheral neurons in response to nerve injury. In vitro and in vivo studies support a central role for Sox11 in adult neuron growth and survival following injury. Brain-derived neurotrophic factor (BDNF) is a pleiotropic growth factor that has effects on neuronal survival, differentiation, synaptic plasticity, and regeneration. BDNF transcription is elevated in the dorsal root ganglia (DRG) following nerve injury in parallel with Sox11, allowing for the possible regulation by Sox11. To begin to assess the possible influence of Sox11, we used reverse transcriptase PCR assays to determine the relative expression of the nine (I-IXa) noncoding exons and one coding exon (exon IX) of the BDNF gene after sciatic nerve axotomy in the mouse. Exons with upstream promoter regions containing the Sox binding motif 5'-AACAAAG-3' (I, IV, VII, and VIII) were increased at 1 or 3 days following axotomy. Exons 1 and IV showed the greatest increase, and only exon 1 remained elevated at 3 days. Luciferase assays showed that Sox11 could activate the most highly regulated exons, I and IV, and that this activation was reduced by mutation of putative Sox binding sites. Exon expression in injured DRG neurons had some overlap with Neuro2a cells that overexpress Sox11, showing elevation in exon IV and VII transcripts. These findings indicate cell type and contextual specificity of Sox11 in modulation of BDNF transcription.
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PMID:Sox11 modulates brain-derived neurotrophic factor expression in an exon promoter-specific manner. 2233 73


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