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

---

Query: EC:2.7.7.49 (reverse transcriptase)
31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Retinoic acid (RA) derived from vitamin A is necessary for, among other things, mammalian embryonic development. Although the impact of RA-dependent gene-regulation on embryonic development has been examined through genetic disruption of the retinoid receptors, the understanding of the underlying molecular mechanism remain unclear, in part, due to the difficulty in identifying RA-regulated genes in an intact embryo. We report here that RA-regulated genes can be identified from total RA-deficient embryos created by retinol-binding protein antisense (RBP-AS) oligodeoxynucleotide treatment in conjunction with differential display. Of the 28 genes isolated, 15 genes matched known genes in the GenBank database and the others either represented EST sequences or encoded novel genes. Semi-quantitative reverse transcriptase-polymerase chain reaction verified that the mRNA levels of mouse DN 38, COL VI 3 alpha, cul-1, alpha-tropomyosin, and PP2A-C alpha were substantially increased, whereas mouse Msh 2, Ndufa2, Ribosomal protein S19, sFRP-1, GDAP-10 and mSmcD were significantly decreased in vitamin A deficient (VAD) embryos compared to the control embryos. The utility of the method is exemplified by our finding that several genes in the Wnt signaling pathway are vitamin A regulated in day 9.0 post coitum (p.c.) embryos.
...
PMID:Identification of known and novel genes whose expression is regulated by endogenous retinoic acid during early embryonic development of the mouse. 1217 13

The frequency of Ty1- copia-type and Ty3- gypsy-type retrotransposons in the International Triticeae EST Consortium (ITEC) database (61,942 sequences: 82% wheat, 10% barley, 8% rye) and the DuPont EST database (86,628 wheat sequences) was estimated using BLASTN searches. These ESTs were obtained from 94 cDNA libraries from different tissues (leaves, roots, spikes, flowers and seeds) and different growing conditions, excluding subtracted and normalized cDNA libraries. Triticeae EST databases were screened using four different Ty1- -copia-type, 12 reverse transcriptase sequences, and three Ty3- gypsy-type Triticeae retrotransposon sequences. Using a selection threshold of BLASTN scores higher than 100 or E values smaller than e(-20), 0.145% of the ESTs were found to be significantly similar to at least one of the retrotransposons used in the search (0.064% Ty1- copia, 0.081% Ty3- gypsy). This percentage increased to 0.176% when the BLASTN threshold was changed to E<e(-10). The percentage of ESTs similar to retrotransposons was significantly higher ( P < 0.05) in cDNA libraries from leaf tissues than in cDNA libraries from roots, anthers, or spikes. In addition, the percentage of ESTs similar to retrotransposons in cDNA libraries from plants under stress conditions (0.25% at E<e(-20), and 0.30% at E<e(-10)) was three to four folds higher ( P < 0.0001) than in cDNA libraries from plants grown under normal conditions (0.07% at E<e(-20), and 0.09% at E<e(-10)). Identification of retrotransposons within the Triticeae EST databases provides an indirect estimation of the patterns of transcriptional activity of these repetitive elements and is important to improve the annotation of genomic sequences used to search these EST databases.
...
PMID:Frequencies of Ty1- copia and Ty3- gypsy retroelements within the Triticeae EST databases. 1258 44

In humans, a polymorphic gene encodes the drug-metabolizing enzyme NAT1 (arylamine N-acetyltransferase Type 1), which is widely expressed throughout the body. While the protein-coding region of NAT1 is contained within a single exon, examination of the human EST (expressed sequence tag) database at the NCBI revealed the presence of nine separate exons, eight of which were located in the 5' non-coding region of NAT1. Differential splicing produced at least eight unique mRNA isoforms that could be grouped according to the location of the first exon, which suggested that NAT1 expression occurs from three alternative promoters. Using RT (reverse transcriptase)-PCR, we identified one major transcript in various epithelial cells derived from different tissues. In contrast, multiple transcripts were observed in blood-derived cell lines (CEM, THP-1 and Jurkat), with a novel variant, not identified in the EST database, found in CEM cells only. The major splice variant increased gene expression 9-11-fold in a luciferase reporter assay, while the other isoforms were similar or slightly greater than the control. We examined the upstream region of the most active splice variant in a promoter-reporter assay, and isolated a 257 bp sequence that produced maximal promoter activity. This sequence lacked a TATA box, but contained a consensus Sp1 site and a CAAT box, as well as several other putative transcription-factor-binding sites. Cell-specific expression of the different NAT1 transcripts may contribute to the variation in NAT1 activity in vivo.
...
PMID:Genomic organization of human arylamine N-acetyltransferase Type I reveals alternative promoters that generate different 5'-UTR splice variants with altered translational activities. 1548 85

The National Institutes of Health's Mammalian Gene Collection (MGC) project was designed to generate and sequence a publicly accessible cDNA resource containing a complete open reading frame (ORF) for every human and mouse gene. The project initially used a random strategy to select clones from a large number of cDNA libraries from diverse tissues. Candidate clones were chosen based on 5'-EST sequences, and then fully sequenced to high accuracy and analyzed by algorithms developed for this project. Currently, more than 11,000 human and 10,000 mouse genes are represented in MGC by at least one clone with a full ORF. The random selection approach is now reaching a saturation point, and a transition to protocols targeted at the missing transcripts is now required to complete the mouse and human collections. Comparison of the sequence of the MGC clones to reference genome sequences reveals that most cDNA clones are of very high sequence quality, although it is likely that some cDNAs may carry missense variants as a consequence of experimental artifact, such as PCR, cloning, or reverse transcriptase errors. Recently, a rat cDNA component was added to the project, and ongoing frog (Xenopus) and zebrafish (Danio) cDNA projects were expanded to take advantage of the high-throughput MGC pipeline.
...
PMID:The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC). 1548 34

Through differential analysis of transcripts (SDDM), 85 cDNA sequences specifically or preferentially expressed in wheat spikelets at heading time were identified and cloned; 54 of them had significant homology with genomic, cDNA and protein and 16 with EST sequences. Among these 54 clones, 44 matched genes with known functions, whereas 10 detected homology with putative genes encoding proteins whose functions have been deduced on the basis of bioinformatic comparisons. Seventeen clones corresponded to genes that had never been cloned in cereals, 5 were related to wheat genes with known functions, and the remaining 32 to genes cloned in other cereals. On the basis of their presumed functions, the 54 clones were assigned to seven groups. The first four of them contained 40 sequences likely involved in floral organ morphogenesis and gametogenesis, and precisely (i) sequences involved in the morphogenesis of floral organs; (ii) sequences expressed in pollen and/or anther tissues; (iii) sequences encoding transcription factors; (iv) sequences involved in signal perception and transduction (kinases and LRR proteins). The expression patterns of these 40 sequences have been studied by reverse transcriptase-polymerase chain reaction (RT-PCR) analysis of transcripts from different tissues and spike organs of wheat.
...
PMID:Identification and characterization of gene sequences expressed in wheat spikelets at the heading stage. 1571 46

PLC (phospholipase C) isoenzymes catalyse the conversion of PtdIns(4,5)P2 into the Ca2+-mobilizing second messenger, Ins(1,4,5)P3, and the protein kinase C-activating second messenger, diacylglycerol. With the goal of identifying additional mammalian PLC isoenzymes, we screened the NCBI non-redundant database using a BLAST algorithm for novel sequences with homology with the conserved PLC catalytic core. Two unique sequences corresponding to two unknown PLC isoenzymes were identified, and one of these, designated PLC-eta2, was cloned and characterized. Most of the coding sequence of PLC-eta2 was constructed from two ESTs (expressed sequence tags), which included an overlapping sequence that was confirmed by multiple ESTs and mRNAs. 5'-RACE (rapid amplification of cDNA ends) also identified an upstream exon not deduced from available EST or mRNA sequences. Sequence analysis of PLC-eta2 revealed the canonical domains of a PLC isoenzyme with an additional long C-terminus that contains a class II PDZ-binding motif. Genomic analyses indicated that PLC-eta2 is encoded by 23 exons. RT-PCR (reverse transcriptase-PCR) analyses illustrated expression of PLC-eta2 in human retina and kidney, as well as in mouse brain, eye and lung. RT-PCR with exon-specific primers also revealed tissue-specific expression of four splice variants in mouse that represent alternative use of sequences in exons 21, 22 and 23. PLC-eta2-specific antisera recognized one of these splice variants as an approx. 155 kDa species when expressed in COS-7 cells; PLC-eta2 natively expressed in 1321N1 human astrocytoma cells also migrated as an approx. 155 kDa species. PLC activity was observed in vitro and in vivo for three different constructs of PLC-eta2, each containing possible alternatively spliced first exons. Co-expression of PLC-eta2 with Gbeta1gamma2 dimers of heterotrimeric G-proteins resulted in marked stimulation of inositol lipid hydrolysis. Thus PLC-eta2 may in part function downstream of G-protein-coupled receptors.
...
PMID:Molecular cloning and characterization of PLC-eta2. 1623 48

NANOG is essential for mouse and human embryonic stem cell (ESC) pluripotency and selfrenewal. It is also expressed in several adult murine tissues as shown by reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. However, human NANOG transcripts have been isolated from adult bone marrow (EST; GenBank accession no. BF893620). Here, we study the NANOG gene expression profile in isolated mouse renal papillary cells by Northern blot and RT-PCR. The whole RNA of mouse renal cells was obtained from fresh renal tissues, renal tissues infused by phosphate-buffered saline (PBS), and isolated renal papillary cells of mouse, respectively, as well as the renal papillary tissue from 18.5 days postcoitum (d.p.c.; fetal), 1-2-week-old (young), 1-8-month-old (adult), and 24-month-old (aging) mice. Our analysis shows that a very low expression level was detected in mouse renal tissues, and the renal papillary cells express more than other tissues as determined with Northern blot and RT-PCR. These data suggest that the kidney has its own cells expressing NANOG, and loss of NANOG expression occurs in an age-dependent manner in the kidney, either due to developmental factors or aging, particularly in renal papillary tissue.
...
PMID:NANOG changes in mouse kidneys with age. 1631 24

Protocadherins (PCDH), localized to synaptic junctions, contribute to the formation of neuronal networks during brain development; thus, it is speculated that protocadherins may play a role in evolution of neuronal complexity. While protocadherin genes are highly conserved in vertebrates, EST evidence from the locus suggests apparently species-specific cis-antisense transcripts. Novel cis-antisense transcripts, which partially overlap the PCDHalpha12 variable exon, PCDHbeta3 single-exon gene, and PCDHpsi5 unprocessed pseudogene in the human 5q31 PCDHalpha/beta/gamma gene cluster and which are coexpressed with sense-strand transcripts in fetal and adult brain, were identified computationally and validated by gene-specific strand-specific reverse transcriptase PCR (SSRTPCR) and sequencing. Absence of antisense transcripts arising from equivalent genomic locations in mouse indicates that the antisense transcripts originated in the primates after the primate-rodent divergence. Furthermore, not all expected orthologues of human sense and antisense PCDH transcripts were detected in rhesus macaque brain, implying that protocadherin expression patterns differ between primate species. RT followed by quantitative real-time PCR (QPCR) analysis of the three genes in the brain of all three species, and of the PCDHbeta15 gene paralogous to PCDHpsi5 in human and rhesus, revealed that the presence of antisense transcripts was significantly associated with lower sense expression levels across all orthologues. This inverse relationship, along with the pattern of sense and antisense coexpression in the brain, is consistent with a regulatory role for the primate-specific PCDH cis-antisense transcripts, which may represent recent evolutionary inventions modulating the activity of this conserved gene cluster.
...
PMID:Primate-specific endogenous cis-antisense transcription in the human 5q31 protocadherin gene cluster. 1634 67

Potato (Solanum tuberosum) plants are rich in 9-lipoxygenase, which converts linoleic acid and alpha-linolenic acid to 9S-hydroperoxy-10E,12Z-octadecadienoic acid (9-HPOD) and 9S-hydroperoxy-10E,12Z,15Z-octadecatrienoic acid (9-HPOT) respectively. The allene oxide synthase (AOS) involved in 9-HPOD/9-HPOT metabolism in potato, however, has not been characterized in detail. We cloned a cDNA encoding a novel AOS from potato sprouts by reverse transcriptase-PCR based on a partial sequence in the EST database. This AOS was successfully expressed in the yeast Pichia pastoris, and purified using Ni-NTA resin. The recombinant enzyme metabolized 9-HPOD, 9-HPOT, 13-HPOD, and 13-HPOT with reaction efficiencies of 2.5 x 10(7), 1.0 x 10(7), 2.5 x 10(6), and 7.6 x 10(6) M(-1) s(-1) respectively. The alpha-ketol formed from 9-HPOD was composed mainly of the 9R-enatimomer (90%). Besides sprouts, the mRNA of this AOS was detected in buds, flowers, and stems, but not in leaves, tubers, or roots of mature plants, suggesting that this enzyme has a tissue-specific function.
...
PMID:Molecular cloning, functional expression, and tissue distribution of a potato sprout allene oxide synthase involved in a 9-lipoxygenase pathway. 1696 Mar 83

We have isolated and characterized a complete retrotransposon sequence, named PpRT1, from the genome of Pinus pinaster. PpRT1 is 5,966 bp long and is closely related to IFG7 gypsy retrotransposon from Pinus radiata. The long terminal repeats (LTRs) have 333 bp each and show a 5.4% sequence divergence between them. In addition to the characteristic polypurine tract (PPT) and the primer binding site (PBS), PpRT1 carries internal regions with homology to retroviral genes gag and pol. The pol region contains sequence motifs related to the enzymes protease, reverse transcriptase, RNAseH and integrase in the same typical order known for Ty3/gypsy-like retrotransposons. PpRT1 was extended from an EST database sequence indicating that its transcription is occurring in pine tissues. Southern blot analyses indicate however, that PpRT1 is present in a unique or a low number of copies in the P. pinaster genome. The differences in nucleotide sequence found between PpRT1 and IFG7 may explain the strikingly different copy number in the two pine species genome. Based on the homologies observed when comparing LTR region among different gypsy elements we propose that the highly conserved LTR regions may be useful to amplify other retrotransposon sequences of the same or close retrotransposon family.
...
PMID:PpRT1: the first complete gypsy-like retrotransposon isolated in Pinus pinaster. 1700 93


<< Previous 1 2 3 Next >>

---