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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The secondary structure of pre-mRNA species from mouse Ehrlich ascites carcinoma cells extracted with phenol at the temperatures either 55-65 degrees C or 65-85 degrees C was investigated. A fraction of the double helical regions of pre-mRNA was estimated by two methods: a) by recording of melting curves; b) by measuring fluorescence lifetimes of acridine orange dye adsorbed on the nucleic acid. This fraction was about 64-68%. Further lowering of ionic strength down to 0.024 results in 10-15% decrease in the fraction of double regions. Both lowering of ionic strength and increase of the temperature up to 50-55 degrees C results in despiralisation of pre-mRNA regions which contain more than 70% of AU-nucleotide pairs. Only regions containing mainly GC-nucleotide pairs remain double-stranded under heating to temperatures above 50 degrees C. These facts were established on the basis of studies of acriflavin dye complexes with pre-mRNA.
Mol Biol (Mosk)
PMID:[Secondary structure of nuclear precursors of the informational RNA (pre-mRNA)]. 105 71

Nuclear 14 S RNP particles containing poly (A) from Ehrlich ascites carcinoma cells and rat liver were purified by re-sedimentation in sucrose gradients, by Cs2SO4 density gradient centrifugation and by affinity chromatography on a poly (dT)-Sepharose column. Proteins of these RNP particles were electrophoresed in urea and SDS-polyacrylamide gels. RNP particles of ascites carcinoma cells contain two main bands having molecular weights of 51 000 and 69 000 daltons, respectively, and two or three minor components.
Mol Biol Rep 1975 Mar
PMID:Protein composition of nuclear 14 S ribonucleoprotein particles containing poly (A). 112 12

The total poly(A)-containing mRNA from mouse liver or Ehrlich ascites carcinoma cells was annealed with denatured ds RNA prepared from heavy nuclear 3H-labeled pre-mRNA of the same tissue. The hybrids formed were detected by binding of complexes to poly(U)-Sepharose columns through the poly(A) of mRNA. With this technique, about 30% of labeled ds RNA was bound to poly(U)-Sepharose after annealing it with an mRNA excess. The proportion of hybrid material detected by RNase treatment was two to three times lower than that obtained by poly(U)-Sepharose binding. The length of the RNase-stable acid precipitable hybrid material consisted of heterogeneous sequences of 10-100 nucleotides long when cytoplasmic, and 10-60 nucleotides long when polysomal mRNA was used in the hybridization reaction. The results obtained show that at least some of the mRNA molecules contain sequences complementary to one of the branches of the pre-mRNA hairpins. These results are compatible with the idea that the hairpin-like sequences in pre-mRNA are localized between mRNA and the non-informative part of the precursor molecule.
Mol Biol Rep 1976 Apr
PMID:Direct demonstration of a complementarity between mRNA and double-stranded sequences of pre-mRNA. 127 59

A new method of simultaneous analysis of the relative abundance of the most abundant individual mRNA's in poly(A)(+)-RNA preparations is described. The method is based on the synthesis of short (10-20 nucleotides) cDNA products by reverse transcription of poly(A)(+)-RNA primed with 5'-labeled oligonucleotides of 9 nucleotide lengths. Three natural nucleotides and one terminator nucleotide are used as substrates for reverse transcriptase. The numbers, lengths and sequence of the oligonucleotides used as primers were chosen to provide more than a 90% probability that synthesis would be initiated from any individual RNA present in the poly(A)(+)-RNA, thus assuring comprehensive analysis of RNA with abundance higher than 0.01%. Each primer produces about 20-60 bands per track following polyacrylamide electrophoresis under denaturing conditions. A full set of 30 oligonucleotides used to analyze a poly(A)(+)-RNA preparation produces an electrophoretic pattern with information capacity similar to that obtained from high resolution 2-dimensional electrophoresis of protein. Using this method we show that the patterns of poly(A)(+)-RNA differ from tissue to tissue, from normal tissues to neoplastic tissue (human myoma of uterus) and during differentiation of a F9 embryonic carcinoma cell line.
Mol Biol (Mosk)
PMID:[Quantitative analysis of individual RNA in preparations of poly(A)+-RNA mammalian cells]. 128 8

We report the identification of a novel cDNA representing an mRNA showing significantly higher levels of expression in benign breast lesions than in carcinomas. This cDNA was identified by differential screening of a cDNA library generated from a breast carcinoma, and shows consistently higher expression in fibroadenomas than in carcinomas. The expression in both benign and malignant tissues is highest in epithelial cells as determined by in situ hybridization to tissue sections. The nucleotide sequence of the full-length cDNA has been determined, and the deduced protein is highly basic with no signal or transmembrane sequence, but two potential nuclear localization signals. Neither the DNA nor the protein sequence show any significant homology to sequences in current databases. The cDNA hybridizes to multiple sequences within both human and other mammalian genomes, but to single genomic sequences in Drosophila, Physarum and Schizosaccharomyces pombe. This cDNA therefore represents a highly conserved gene sequence. We have identified only one major transcript in human cells, and it seems likely that there are several pseudogenes within the human genome.
Hum Mol Genet 1992 May
PMID:Isolation and characterization of a novel gene with differential expression in benign and malignant human breast tumours. 130 Nov 62

In a number of types of cancer including breast, hepatocellular, and bladder carcinoma, frequent losses of heterozygosity (LOH) on chromosome 11p15 have indicated the presence of one or more tumor suppressor genes in this region. In the present study, we report the detection and characterization of a rearrangement at 11p15 in a sporadic breast carcinoma. Genomic DNA clones encompassing the rearranged region were isolated; localization of both flanking clones to 11p15 by two-color fluorescent in situ hybridization (FISH) indicated that the rearrangement was caused by an interstitial deletion in the affected allele. Although it is uncertain whether the region between the flanking two loci was missing from tumor cells, our result implied that a putative tumor suppressor gene on chromosome 11p15 is located between the loci on either side of the interstitial deletion or may be interrupted by one of the breakpoints.
Hum Mol Genet 1992 Dec
PMID:Cloning and characterization of an interstitial deletion at chromosome 11p15 in a sporadic breast cancer. 130 7

Apolipoprotein CIII (apoCIII), a lipid-binding protein involved in the transport of triglycerides and cholesterol in the plasma, is synthesized primarily in the liver and the intestine. A cis-acting regulatory element, C3P, located at -90 to -66 upstream from the apoCIII gene transcriptional start site (+1), is necessary for maximal expression of the apoCIII gene in human hepatoma (HepG2) and intestinal carcinoma (Caco2) cells. This report shows that three members of the steroid receptor superfamily of transcription factors, hepatocyte nuclear factor 4 (HNF-4), apolipoprotein AI regulatory protein 1 (ARP-1), and Ear3/COUP-TF, act at the C3P site. HNF-4 activates apoCIII gene expression in HepG2 and Caco2 cells, while ARP-1 and Ear3/COUP-TF repress its expression in the same cells. HNF-4 activation is abolished by increasing amounts of ARP-1 or Ear3/COUP-TF, and repression by ARP-1 or Ear3/COUP-TF is alleviated by increasing amounts of HNF-4. HNF-4 and ARP-1 bind with similar affinities to the C3P site, suggesting that their opposing transcriptional effects may be mediated by direct competition for DNA binding. HNF-4 and ARP-1 mRNAs are present within the same cells in the liver and intestine, and protein extracts from hepatic tissue, HepG2, and Caco2 cells contain significantly more HNF-4 than ARP-1 or Ear3/COUP-TF binding activities. These findings suggest that the transcription of the apoCIII gene in vivo is dependent, at least in part, upon the intracellular balance of these positive and negative regulatory factors.
Mol Cell Biol 1992 Apr
PMID:Antagonism between apolipoprotein AI regulatory protein 1, Ear3/COUP-TF, and hepatocyte nuclear factor 4 modulates apolipoprotein CIII gene expression in liver and intestinal cells. 131 68

The insert of 1278 bp containing the entire coding region of cDNA encoding human 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) was inserted into a pHS1 vector and expressed in HeLA human cervical carcinoma cells and COS-1 monkey kidney tumor cells. Western blot analysis indicated that the expressed protein migrates at the same position as the purified enzyme and is recognized by the antibody raised against purified human placental 17 beta-HSD. The expressed enzyme efficiently catalyzes the interconversion of estrone and estradiol while dehydroepiandrosterone and 5-androstene-3 beta,17 beta-diol are interconverted at a lower rate. The present data suggest the existence of two 17 beta-HSDs.
J Steroid Biochem Mol Biol 1992 Mar
PMID:Expression of human 17 beta-hydroxysteroid dehydrogenase in mammalian cells. 131 81

Regulation of androgen receptor (AR) mRNA expression was studied in Sertoli cells and peritubular myoid cells isolated from immature rat testis, and in the lymph node carcinoma cell line derived from a human prostate (LNCaP). Addition of dibutyryl-cyclic AMP (dbcAMP) to Sertoli cell cultures resulted in a rapid transient decrease in AR mRNA expression (5 h), which was followed by a gradual increase in AR mRNA expression (24-72 h). This effect of dbcAMP mimicked follicle-stimulating hormone (FSH) action. In peritubular myoid cells, there was only a moderate but prolonged decrease during incubation in the presence of dbcAMP, and in LNCaP cells no effect of dbcAMP on AR mRNA expression was observed. When Sertoli cells or peritubular myoid cells were cultured in the presence of androgens, AR mRNA expression in these cell types did not change. This is in contrast to LNCaP cells, that showed a marked reduction of AR mRNA expression during androgen treatment. In the present experiments, transcriptional regulation of AR gene expression in Sertoli cells and LNCaP cells was also examined. Freshly isolated Sertoli cell clusters were transfected with a series of luciferase reporter gene constructs, driven by the AR promoter. It was found that addition of dbcAMP to the transfected Sertoli cells resulted in a small but consistent increase in reporter gene expression (which was interpreted as resulting from AR promoter activity); a construct that only contained the AR 5' untranslated region of the cDNA sequence did not show such a regulation. The same constructs, transfected into LNCaP cells, did not show any transcriptional down-regulation when the synthetic androgen R1881 was added to the cell cultures. A nuclear transcription elongation experiment (run-on), however, demonstrated that androgen-induced AR mRNA down-regulation in LNCaP cells resulted from an inhibition of AR gene transcription. The present results indicate that in Sertoli cells and LNCaP cells, hormonal effects on AR gene transcription play a role in regulation of AR expression. However, AR gene transcription in these cells is differentially regulated.
Mol Cell Endocrinol 1992 Oct
PMID:Transcriptional regulation of androgen receptor gene expression in Sertoli cells and other cell types. 133 8

Point-mutational activation of the c-Ki-ras proto-oncogene has been shown to be rare in human hepatocellular carcinoma, the most common primary liver cancer and one usually associated with chronic viral infection. To reveal the association of c-Ki-ras activation with cholangiocarcinogenesis under different etiological backgrounds, the incidence of point mutation at codons 12 and 13 of the c-Ki-ras proto-oncogene was examined in three groups of human liver cancers with differentiation to biliary epithelial cells: Group 1, cholangiocellular carcinoma in Japanese with normal livers; Group 2, cholangiocellular carcinoma in Thais who had lived in an area where the liver fluke Opisthorchis viverrini is endemic; and Group 3, combined hepatocellular-cholangiocellular carcinoma, a rare type showing features of both hepatocellular and biliary epithelial differentiation, in Japanese with chronic viral hepatitis with or without cirrhosis. The polymerase chain reaction and direct sequencing of its product were used to detect the mutation. Point mutation at codon 12 of the c-Ki-ras gene was detected in five (56%) of nine cases in Group 1. In contrast, the mutation was not detected in any of the cases in Groups 2 and 3. Therefore, point-mutational activation of c-Ki-ras did not seem to be involved in the development of primary liver cancers associated with apparent chronic irritation of liver cells or biliary epithelial cells caused by exogenous liver-fluke or viral infection. On the other hand, point-mutational activation of the c-Ki-ras proto-oncogene may be involved in cholangiocarcinogenesis in liver without preexisting liver-fluke or viral infection.
Mol Carcinog 1992
PMID:Cholangiocarcinomas in Japanese and Thai patients: difference in etiology and incidence of point mutation of the c-Ki-ras proto-oncogene. 133 66


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