Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.7.48 (transcriptase)
9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. To identify and isolate cDNAs encoding rat and human bradykinin-B2 receptor subtypes we isolated a human bradykinin receptor cDNA homologous to a rat B2 receptor cDNA. 2. The cDNA was expressed in the bradykinin receptor negative cell line, CHO; membranes prepared from these cells bound bradykinin and had specificity similar to that of the known rat B2 receptor. In addition, the expressed receptor has a low affinity for des-Arg9-bradykinin. Thus, the cDNA encodes a human B2-bradykinin receptor. 3. Comparison of the human and rat cDNAs suggested that the human and rat genes are composed of three exons. Cloning, sequencing and characterization of parts of the human and rat B2-bradykinin receptor genes demonstrated the postulated three-exon structure. This structure includes two 5' exons upstream of the most favorable translation initiation methionine in exon-3. 4. The two 5' exons each contain methionines, which if independently spliced to the third exon, would yield an open reading frame that includes all of exon-3. This arrangement could thus vary the amino-terminal region of the protein. Do these potential arrangements occur in human RNAs, and will they lead to proteins with differing amino-termini? 5. Reverse transcriptase-polymerase chain reactions (RT-PCR) using human mRNA, nested primers from exon-1 and exon-3, and detection of the products by hybridization using an independent exon-1 oligonucleotide showed that the arrangement of exon-1 with exon-2 and exon-3 could not be detected in eight human RNAs. Furthermore, exon-1 spliced with exon-3 was a common arrangement. 6. Low stringency examination of human and rat Southern blots revealed only bands attributable to the known human or rat B2-bradykinin receptor. 7. Reduced stringency hybridization searches of seven different genomic and cDNA libraries--including two different human genomic libraries, a rat genomic library, two different rat uterus cDNA libraries, a rat brain library and a human lung library--yielded only rat or human B2-bradykinin receptors. The results of our low stringency hybridization experiments suggest that other bradykinin receptors are less than 60% identical, on the nucleotide level, to the known B2 receptor. 8. Degenerate polymerase chain reactions using rat genomic DNA as a template and degenerate primers, designed based on the homology of a B2-bradykinin receptor with angiotensin-II type-1 receptor, identified B2-bradykinin receptors, angiotensin-II-type-1 receptors and three novel orphan receptors.
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PMID:Bradykinin-B2 receptors in humans and rats: cDNA structures, gene structures, possible alternative splicing, and homology searching for subtypes. 753 72

The fibronectin receptor, alpha 5 beta 1, may be involved in many aspects of early development, including migration of endodermal and mesodermal cells during formation of the placenta, trophoblastic outgrowth in culture, and development of an invasive phenotype by fetal cytotrophoblasts. In contrast to the human blastocyst, the bovine blastocyst elongates in the uterine lumen for several days until it begins attachment, and the fetal trophoblast limits its invasion to the maternal epithelium. Fibronectin receptor expression was characterized in bovine embryos before and after their attachment to the uterus. Initially, the polymerase chain reaction (PCR) was conducted with degenerate oligonucleotide primers to isolate bovine cDNAs for the alpha 5 and beta 1 subunits. Bovine-specific primers were then constructed to assay for alpha 5 and beta 1 mRNA expression in embryo RNA during the morula through the attachment stages using reverse-transcriptase PCR. Northern blot analysis was used to quantify mRNA levels from Days 15 to 21. Integrin and fibronectin protein expression was assessed by immunohistochemical examination of embryo sections. Both alpha 5 and beta 1 subunit mRNAs were expressed throughout the stages examined. Expression of both subunit proteins was found in the endoderm at Day 14 but not at Day 18 or later. Fibronectin reactivity was not present at any of the stages examined. Between Days 18 and 21, beta 1-reactivity appeared on the lateral surfaces of the trophoblast cells. Day 24 trophoblast binucleate cells showed intense staining with the beta 1 antibody, suggesting that a beta 1-integrin is involved in binucleate cell migration.
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PMID:Fibronectin receptors in preimplantation development: cloning, expression, and localization of the alpha 5 and beta 1 integrin subunits in bovine trophoblast. 754 39

1. Kallikrein enzyme activity has been previously reported in the uterus of several species and implicated in implantation and parturition. In order to provide further evidence for a local kallikrein-kinin system in this tissue, we wished to determine if the gene encoding kallikrein (KLK1) was expressed in the human uterus and determine the pattern of its expression across the menstrual cycle. 2. Reverse-transcriptase polymerase chain reaction (RT-PCR) of endometrial and myometrial total RNA coupled with Southern blot analysis showed that KLK1 was expressed in the human endometrium and myometrium. Endometrial expression of KLK1 was confirmed by DNA sequence analysis of the PCR products. Kallikrein was also localized by immunocytochemistry, primarily in the glandular epithelium of the endometrium. 3. Quantitative RT-PCR of 37 endometrial samples ranging from day 1 to 29 from across the menstrual cycle showed significantly higher KLK1 (kallikrein) expression from the mid proliferative to the early secretory phase compared with the late secretory and menstrual phases. 4. We have demonstrated for the first time that KLK1, the gene encoding glandular kallikrein, is expressed in the human uterus. The increase in endometrial KLK1 gene expression during the proliferative phase of the menstrual cycle suggests a role for kallikrein in the preparation of the endometrial lining for implantation.
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PMID:Glandular kallikrein gene expression in the human uterus. 774 74

A cDNA coding for the beta 4 subunit of murine integrin (m beta 4) has been cloned and sequenced using mRNA from a murine lung carcinoma as the template. The 5' sequence contains two AUG codons, the second of which initiates synthesis of the mature protein. The cDNA sequence has an open reading frame coding for 1748 amino acids (aa), including a signal peptide, cysteine-rich region, serine- and threonine-rich region, transmembrane domain, and a cytoplasmic domain of over 1000 aa. Overall, the deduced m beta 4 aa sequence has 88% identity with the human beta 4 subunit (h beta 4) sequence deduced from the sequence of placental mRNA. Reverse transcriptase-polymerase chain reaction using primers flanking splice sites for two variant forms of h beta 4 transcripts provided evidence for alternate splicing of RNA in the murine spleen and to a lesser extent in the skin, uterus, and thymus but was found at only one of the two alternative sites. Five potential glycosylation sites present in the extracellular domain of h beta 4 are conserved in m beta 4. One tyrosine in the terminal region of the cytoplasmic domain (position 1600) is conserved between m beta 4 and h beta 4 and has the consensus sequence for tyrosine phosphorylation. Finally, a genomic restriction map of m beta 4 shows that the gene is about 40 kb in length. No restriction-fragment length polymorphisms were detected between BALB/c liver and BALB/c lung carcinoma DNA.
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PMID:Sequence of a cDNA encoding the beta 4 subunit of murine integrin. 835 87

Reproductive and maturational nutritive needs are examples of situations in which alterations in circulating concentrations of estrogens are associated with changes in intestinal epithelial function. However, it is not clear that any of these effects is due to direct interaction of estrogen with intestinal epithelial estrogen receptors (ER). The experiments reported here were designed to determine whether the small intestinal epithelium contains functional ER and might, therefore, be an estrogen-responsive tissue. IEC-6 cells, a non-transformed line of cells isolated from rat small intestinal crypts, were used for many of the experiments, because they provide a pure preparation of crypt epithelial cells. IEC-6 cells were found to exhibit specific saturable binding of estradiol with a Kd of 5 x 10(-10) M and approximately 100 binding sites/cell. Reverse transcriptase-polymerase chain reaction demonstrated that IEC-6 cells as well as epithelial cells from each segment of the rat intestine (duodenum, jejunum, ileum, and colon) contained ER mRNA of the sequence determined from rat uterus. Estradiol was shown to stimulate IEC-6 cell c-fos mRNA content rapidly and transiently in a manner analogous to that which has been previously demonstrated for other estrogen-responsive tissues. These data demonstrate that intestinal epithelial cells contain ER capable of regulating gene transcription and provide the basis for future studies designed to elucidate the role of estrogens in the regulation of intestinal epithelial function and pathophysiology.
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PMID:The presence of functional estrogen receptors in intestinal epithelial cells. 841 41

We previously established transplantable rat thyroid carcinoma cell lines in vivo from primary thyroid tumors induced by N-bis-(2-hydroxypropyl)nitrosamine (DHPN). In the present study, an insulin-like growth factor I (IGF-I)-responsive cell line (TRTC-G1-C-A4) in culture was derived from one (well differentiated papillary type) of these carcinoma cell lines G1. TRTC-G1-C-A4 cells were found to exhibit specific saturable binding of IGF-I with a Kd of 1.16 nM at approximately 43.6 fmol/10(5) cells. Inclusion of IGF-I (10 and 50 ng/ml) in the culture medium resulted in a significant increase of [3H]thymidine incorporation and marked cell proliferation. IGF-II (10 ng/ml) and insulin (1 microgram) produced no such effects. The molecular weight of IGF-I receptors on the cell membrane was determined by Western blotting analysis, a single band of binding proteins with a molecular weight of 125 kDa being evident under non-reducing conditions. Reverse transcriptase polymerase chain reaction (RT-PCR) showed that the TRTC-G1-C-A4 cells contained IGF-I receptor mRNA with a sequence corresponding to that determined from rat uterus. These results demonstrate that the IGF-I receptor can be expressed in a thyroid carcinoma with an important contribution to cell growth.
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PMID:Establishment of a rat thyroid carcinoma cell line in vitro demonstrating high DNA synthesis in response to insulin-like growth factor I. 862 Apr 77

Interleukin-1 (IL-1) plays an important role in implantation of the early embryo since blockade of the IL-1 receptor prevents implantation in the mouse. Whether IL-1 blockade during implantation has a direct effect on the embryo or only the uterus is unknown since reliable data are not available concerning the expression of IL-1 or IL-1 receptor on the preimplantation embryo. Because of the significant role for IL-1 in implantation, we investigated the potential for an embryonic-maternal IL-1 signaling mechanism during mouse preimplantation embryo development. Reverse transcriptase-polymerase chain reaction (RT-PCR) was performed for IL-1 alpha, IL-1 beta and IL-1 receptor type I (IL-1R) on mRNA isolated from mouse preimplantation embryos and uteri collected between the 2-cell to blastocyst stage. Preimplantation embryos have the capability to produce IL-1 beta after the 4-cell stage of development since IL-1 beta mRNA was detected from the 4-cell to blastocyst stage but not at the 2-cell stage. Unlike IL-1 beta, IL-1 alpha was not expressed in preimplantation embryos. It is unlikely that IL-1 has a direct effect on the preimplantation embryo since IL-1R mRNA was not expressed in preimplantation embryos. In contrast, IL-1 could have a direct effect on the uterus since IL-1R mRNA was found to be expressed in uteri at all developmental time points. Our findings suggest that there is a potential embryonic-maternal IL-1 signaling mechanism through the expression of IL-1 beta by the preimplantation embryo and the expression of IL-1R in the uterus.
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PMID:The expression of interleukin-1 alpha, interleukin-1 beta, and interleukin-1 receptor type I mRNA during preimplantation mouse development. 895 18

We have reported that i.v. administration of splenocytes prepared from early pregnant mice promoted embryo implantation in pseudopregnant CD-1 (ICR) (closed colony) mice. In this study, the similar effects of splenocytes were confirmed using an inbred strain, BALB/c mice, and the mechanism was further investigated. Splenocytes were prepared from pregnancy day 4 (P4-spl) and dioestrus mice (Di-spl), and supernatant of P4-spl suspension (P4-sup) was used as controls. On pseudopregnancy day 2, splenocytes or supernatant were injected into caudal vein or endometrial stroma of the recipient mice, and blastocysts were transferred into the endometrial lumen. In both BALB/c and ICR strains, the implantation rates per recipient with i.v. and intraendometrial injection were significantly higher in P4-spl groups. Then, ICR mice were oophorectomized on pseudopregnancy day 3. After 3 day progesterone supplementation, blastocysts were transferred with i.v. injection of P4-spl and P4-sup, or s.c. oestradiol injection. Under progesterone supplementation, successful implantations were observed in the P4-spl- and oestradiol-treated groups, but not in P4-sup-treated group. Reverse transcriptase-polymerase chain reaction analysis revealed that messenger RNA expression of leukaemia inhibitory factor in the uterus was induced by P4-spl and oestradiol, but not by P4-sup. These findings showed that splenocytes of early pregnant mice promote embryo implantation by regulating endometrial differentiation.
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PMID:Splenocytes in early pregnancy promote embryo implantation by regulating endometrial differentiation in mice. 940 62

Many peripheral reproductive tissues have been found to contain gonadotrophin-releasing hormone (GnRH) and express the GnRH gene at low levels, presumably because the hormone functions in a paracrine/autocrine fashion. This study was designed to investigate and characterize GnRH gene expression in human endometrial tissue at different stages of the endometrial cycle. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis together with Southern blot assay demonstrated that human endometrial tissue expresses the proGnRH gene. RNA samples from endometrial tissue were analysed with two pairs of oligonucleotide primers. Both gave a doublet 870 bases apart at the expected sizes, indicating that both the upstream and downstream transcriptional start sites of the GnRH gene are used in endometrial tissue and that transcripts with and without intron 1 were produced. Our data also demonstrated that utilization of the two promoters varies with the stage of the endometrial cycle. The largest difference came from the mRNA transcribed from the downstream promoter and without intron 1. This mRNA was expressed at a very low level during the proliferative phase and dramatically increased almost 10-fold (P < 0.01) during the early secretory phase, and subsequently decreased 5-fold during the late secretory stage. The presence of GnRH mRNA in the endometrium, as well as the differential expression of the GnRH gene during the early secretory phase provides physiological evidence that human GnRH may play a paracrine/autocrine function in the human uterus.
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PMID:Expression of gonadotropin-releasing hormone (GnRH) gene in human uterine endometrial tissue. 978 51

We have previously reported that intravenous administration of splenocytes prepared from mice in the early stages of pregnancy promoted embryo implantation in pseudopregnant mice. Since a T-lymphocyte-rich, but not a monocyte-rich preparation from splenocytes enhanced embryo implantation, similar effects of thymocytes from non-pregnant mice on implantation were examined in this study. Thymocytes were prepared from immature 21 day old ICR female mice and the supernatant of a thymocyte suspension (Th-sup) was used as the control. Thymocytes or Th-sup were injected into the caudal vein of recipient mice on pseudopregnancy day 2, and blastocysts were transferred into the endometrial lumen. The implantation rates per recipient were significantly higher in the thymocyte-treated group. ICR mice were then oophorectomized on pseudopregnancy day 3. After 3-day progesterone supplementation, blastocysts were transferred with intravenous injection of thymocytes or Th-sup. Under progesterone supplementation, successful implantations were observed in the thymocyte-treated group, but not in the Th-sup-treated group. Reverse transcriptase-polymerase chain reaction analysis revealed that mRNA expression of leukaemia inhibitory factor in the uterus was induced by thymocyte administration, but not by Th-sup. Thymocytes were divided into two populations, CD4(+/-)CD8(-) group and CD4(-)CD8(+/-) group, by separation columns. On pseudopregnancy day 2, the separated thymocytes in each group or their supernatant were injected into the endometrial stroma of the recipient mice, and blastocysts were transferred into the endometrial lumen. The administration of CD4(+/-) CD8(-) lymphocytes significantly promoted implantation rates, but no effect was observed in the CD4(-) CD8(+/-) group. These findings showed that thymocytes, especially CD4-positive lymphocytes, facilitate embryo implantation, probably by regulating endometrial differentiation.
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PMID:Administration of thymocytes derived from non-pregnant mice induces an endometrial receptive stage and leukaemia inhibitory factor expression in the uterus. 980 51


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