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At least 37 records · Page 2Linked to original sources
PubMed2001

Perforant path lesion induces up-regulation of stathmin messenger RNA, but not SCG10 messenger RNA, in the adult rat hippocampus.

In this study, we performed in situ hybridization analysis of the expression pattern of two growth-associated proteins, stathmin and SCG10, in the hippocampus after unilateral lesion of the perforant pathway, the main excitatory input from the entorhinal cortex to the hippocampus. Stathmin is one of the major neural-enriched cytosolic phosphoproteins and a potential target of cyclic-AMP-dependent kinases [Jin L. W. et al. (1996) Neurobiol. Aging 17, 331-341; Leighton I. A. et al. (1993) Molec. Cell Biochem. 127/128, 151-156]. Three days after the lesion, stathmin messenger RNA was up-regulated ipsilaterally in the hilus, in the granule cell layer of the dentate gyrus and in the pyramidal cell layer of the CA1 region. Simultaneously, the hilar region of the contralateral dentate gyrus showed an increased stathmin messenger RNA expression. This altered expression pattern was observed until 15 days after lesion. Stathmin messenger RNA expression returned to a normal level until 21 days after lesion in all regions analysed. SCG10, a membrane-bound neuronal growth-associated protein belonging to the SCG10/stathmin gene family, did not show any alteration of messenger RNA expression after perforant path lesion. The temporal changes of stathmin messenger RNA expression in the ipsilateral hippocampus correspond well to the process of reactive synaptogenesis. The enhanced messenger RNA expression in the hilar region of the contralateral dentate gyrus might suggest a role in neurite elongation, since this region is the origin of commissural fibres involved in the sprouting response in the deafferented hippocampus. The present study provides evidence that the induction of specific growth-associated proteins is differentially regulated in the hippocampus.

Animals↗
PubMed1983

Polyribosome binding of rabbit globin messenger RNA and messenger ribonucleoprotein labelled with bacteriophage-T4 RNA ligase and 5'-[32P] phosphocytidine 3'-phosphate.

Rabbit polyribosomal globin messenger RNA (mRNA) and messenger ribonucleoprotein (mRNP) were labelled at the 3' poly(A) tail to high specific activity with T4 RNA ligase and [5'-(32)P]pCp without consequent loss of functional activity. Labelled message was translated in both micrococcal nuclease treated and untreated rabbit reticulocyte lysates, as shown by the formation of labelled polyribosomes. The utilisation of labelled messenger was abolished by T2 toxin or sodium fluoride which are known to inhibit protein synthesis.Images

Animals↗
PubMed1980

Homologies among ribosomal RNA and messenger RNA genes in chloroplasts, mitochondria and E. coli.

Labelled chloroplast rRNAs from Spinacia oleracea were hybridized to restriction endonuclease digests of chloroplast DNA from Oenothera hookeri and Euglena gracilis, to mitochondrial DNA of Acanthamoeba castellanii, and to DNA of the E. coli rrn B operon in the transducing phage lambda rifd 18. The degree of homology is greatest for the 16S rRNA gene. Greater than 90% occurs between the two higher plant genes, 80% homology to the lower plant gene, 60%-70% homology to the bacterial gene, and 20% homology to the mitochondrial gene. The degree of hybridization varied considerably for the 23S and the 5S rRNA genes. Very high homology exists between the two higher plant genes, only about 50% homology for both the Euglena and bacterial genes, and no significant homology for the mitochondrial genes. These results show that any chloroplast (or E. coli) rRNA may be used as a probe to identify rRNA genes in other ctDNAs. Two RNA populations, each enriched for a different ctDNA-encoded mRNA, proved useful in the location of these genes on both higher plant ctDNAs. No significant hybridization was obtained using these probes to the Euglena ctDNA which seems to be too distantly related.

Amoeba↗
PubMed1988

Interaction of Escherichia coli ribosomal protein S8 with its binding sites in ribosomal RNA and messenger RNA.

The ability of ribosomal protein S8 from Escherichia coli to interact with 12 variants of its 16 S rRNA binding site, as well as with a regulatory sequence within spc operon mRNA, has been assessed. Single-site alterations were introduced into the appropriate segment of the E. coli 16 S rRNA gene by mutagenesis in vitro. Their effects on S8-rRNA interaction were measured via a filter-binding assay, utilizing S8 binding sites transcribed in vitro from the altered 16 S rRNA gene fragments. Of the 12 rRNA mutants, six were unable to bind S8. Significantly, five of these occur within a small, phylogenetically conserved internal loop, defined by nucleotides 596-597 and 641-643, suggesting that this structure plays a major role in S8-16 S rRNA recognition. The reduced affinity of S8 for its binding site in these cases was closely correlated with growth defects that resulted from expression of the same mutations in vivo. Alterations at other positions in the S8 binding site had little influence on complex formation or cell growth, as long as they did not disrupt rRNA secondary structure. The specific interaction of S8 with a segment of the spc operon mRNA containing a putative site of translational feedback regulation was demonstrated using appropriate in vitro transcripts in conjunction with the filter-binding assay. The apparent association constant for the S8-mRNA interaction was determined to be approximately 5 x 10(6) M-1, about five times lower than for the interaction of S8 with wild-type 16 S rRNA. The structure of the regulatory binding site, determined by sequence analysis of spc operon mRNA protected by S8 from RNase digestion, was found to contain all of the characteristic features of the 16 S rRNA binding site, demonstrating that the protein associates with structurally similar domains in both RNAs.

Base Sequence↗
PubMed1975

Metabolism of the polyadenylate sequence of nuclear RNA and messenger RNA in mammalian cells.

The poly(A) sequences at the 3' end of mRNA and nuclear RNA molecules of mouse sarcoma and Chinese hamster cells are subject to an elongation process distinct from de novo synthesis. This process continues in cells treated with a high level of actinomycin D to block transcription. This results in the labeling of the steady-state poly(A) population in the cytoplasm and of unusually long poly(A) segments in the nucleus. In cells incubated with 3H-adenosine in the absence of drug treatment, cytoplasmic steady-state poly(A) segments with short labeled sequences at the 3' end can be detected by their heterogenous size distribution and by measurements of adenosine and AMP released by alkaline hydrolysis. These measurements indicate an average size of 8 residues for the labeled sequences. In the nucleus, a slow elongation of preexisting poly(A) chains can also be detected through measurements of AMP and adenosine. The cytoplasmic elongation process leads to turnover of the 3' end of the poly(A) sequence on mRNA, because of concomitant removal of AMP residues. It is apparently not linked to mRNA translation. The Chinese hamster and mouse sarcoma cells appear to differ markedly with respect to relative extents of poly(A) chain extension and de novo synthesis.

Adenine Nucleotides↗
PubMed1973

Relationship between post-transcriptional adenylation of herpes virus RNA and messenger RNA abundance.

Analysis of the hybridization kinetics of labeled DNA of herpes simplex virus with unlabeled excess RNA from infected cells showed that viral RNA sequences form two classes differing in molar concentration. The abundant class constituted 93.5-99.3% of total virus-specific RNA and was complementary to 14-16% of the early DNA (2 hr after infection) and to 19-22% of the late DNA (8 hr after infection) in the reproductive cycle of the virus. The early RNA sequences were found to be a subset of the late sequences. The scarce sequences constituted 0.7-6.5% of total virus-specific RNA and were complementary to 28-30% of DNA both early and late in the reproductive cycle. In this study, abundant and scarce sequences were quantitatively separated on the basis of the finding that abundant species are adenylated, i.e., contain post-transcriptionally added poly(A), whereas the scarce RNA is not. Thus, nuclear and polyribosomal adenylated RNA were complementary to 24 and 22%, respectively, of viral DNA and, in abundance competition tests, were found to compete with each other and with abundant RNA from infected cells after 8 hr. The nonadenylated polyribosomal RNA was complementary to 27% of total viral DNA of which 6% was also complementary to adenylated polyribosomal RNA. Hybridization kinetics indicated that each of the fractionated adenylated RNA formed two classes complementary to 6 and 21% of viral DNA.

Adenine Nucleotides↗
PubMed1982

Effect of anthracycline analogues on the appearance of newly synthesized total RNA and messenger RNA in the cytoplasm of erythroleukemia cells.

Effects of the structural analogues, adriamycin (ADM), daunomycin (DNM), carminomycin (CMM), 4-demethoxydaunomycin (4D-DNM), pyrromycin (PYM), marcellomycin (MCM), and aclacinomycin (ACM) upon total cell RNA synthesis and the appearance of total RNA and poly(A)+-RNA in the cytoplasm of uninduced Friend erythroleukemia cells were investigated. The anthracyclines inhibited cellular RNA synthesis with IC50 values of 1-3 microM (ADM, DNM), 0.3-0.5 microM (CMM, 4D-DNM, PYM), and 0.06 microM (MCM, ACM). IC50 values for the appearance of total RNA in the cytoplasm were consistently 2-3 times lower than those for total cell RNA synthesis for each anthracycline. IC50 values for the inhibition of poly(A)+-RNA in the cytoplasm by ADM, DNM, and CMM were equivalent to those for total RNA synthesis. The values for MCM and ACM were 2-3 times higher than those for total RNA synthesis. The kinetic actions of drug-induced inhibition of poly(A)+-RNA appearance in the cytoplasm and inhibition of total RNA synthesis were equivalent for ADM, DNM and CMM, whereas the other anthracyclines showed different kinetics. These studies confirm the greater sensitivity of nucleolar RNA synthesis to Class II anthracyclines in erythroleukemia cells and suggest that inhibition of post-transcriptional events may occur in cells exposed to PYM, MCM, and ACM but at higher concentrations than are required for inhibition of RNA synthesis.

Animals↗
PubMed1978

Increased activity of rat liver messenger RNA and of albumin messenger RNA modulated by thioacetamide.

Administration of thioacetamide to rats was found to increase the activity of liver messenger RNA in the wheat germ protein synthesis assay. The synthesis of total protein was increased about 2.5-fold after 4 days of treatment. The treatment was associated with an increase in the relative quantity of polyadenylic acid-containing RNA. Immunoprecipitation studies showed that albumin synthesis directed by the messenger RNA was increased disproportionately, reaching a level 5 to 6 times the control after 4 days of thioacetamide administration.

Acetamides↗
PubMed1980

Effect of adriamycin on the polyribosome and messenger-RNA content of rat heart muscle.

The myocardial contents of DNA, protein, total and polyribosomal RNA, messenger RNA (mRNA) and polyribosomes were determined in normal and adriamycin-treated rats. While the myocardial contents of DNA and protein changed only little in adriamycin-treated rats, total and polyribosomal RNA decreased by 23.2% and 35%, mRNA and polyribosomes by 51.6% and 38.7%. Size distribution and protein synthetic activity of the polyribosome preparations obtained remained unchanged in the adriamycin-treated rats. We conclude that the reduced myocardial contents of RNA, mRNA and polyribosomes cause the previously observed impairment of myocardial protein synthesis in adriamycin-treated rats and might be important in the pathogenesis of the adriamycin-cardiomyopathy.

Animals↗
PubMed1981

Poly(adenylic acid)-containing and -deficient messenger RNA of mouse liver.

RNA was isolated and fractionated into poly(A)-containing and -deficient classes by oligo(dT) chromatography. Approximately 99% of the poly(A) material bound to the oligo(dT); that which did not bind contained substantially shorter poly(A) chains. All RNA fractions retained an ability to initiate cell-free translation, with the poly(A)-deficient fraction containing half the total translational activity, i.e., mRNA. Two-dimensional polyacrylamide gel analysis of the cell-free translation products revealed three classes of mRNA: 1, mRNA preferentially containing poly(A), including the abundant liver mRNA species; 2, poly(A)-deficient mRNA, including many mid- and low-abundant mRNAs exhibiting less than 10% contamination in the poly(A)-containing fraction fraction; and 3, bimorphic species of mRNA proportioned between both the poly(A)-containing and -deficient fractions. Poly(A)-containing and bimorphic mRNA classes were further characterized by cDNA hybridizations. The capacity of various RNA fractions to prime cDNA synthesis was determined. Compared to total RNA, the poly(A)-containing RNA retained 70% of the priming capacity, while 20% was found in the poly(A)-deficient fraction. Poly(A)-containing, poly(A)-deficient, and total RNA fractions were hybridized to cDNAs synthesized from (+)poly(A)RNA. Poly(A)-containing RNA hybridized with an average R0t 1/2 approximately 20 times faster than total RNA. Poly(A)-deficient RNA hybridized with an average R0t 1/2 approximately 3-4 times slower than total RNA. These R0t 1/2 shifts indicated that in excess of three-quarters of the total hybridizable RNA was recovered in the poly(A)-containing fraction and that less than one-quarter was recovered in the poly(A)-deficient RNA fraction. Abundancy classes were less distinct in heterologous hybridizations. In all cases the extent of hybridization was similar, indicating that while the amount of various mRNA species varied among the RNA fractions, most hybridizing species of RNA were present in each RNA fraction. cDNA to the abundant class of mRNAs was purified and hybridized to both (+)- and (-)poly(A)RNA. Messenger RNA corresponding to the more abundant species was enriched in the poly(A)-containing fraction at least 2-fold over the less abundant species of mRNA, with less than 10% of the abundant mRNAs appearing inthe poly(A)-deficient fraction.

Animals↗