scholarly journals Expression and developmental regulation of two unique mRNAs specific to brain membrane-bound polyribosomes

1987 ◽  
Vol 244 (2) ◽  
pp. 359-366 ◽  
Author(s):  
C Hall ◽  
C M Lowndes ◽  
T K Leung ◽  
D N Cooper ◽  
A M Goate ◽  
...  

Translation in vitro of membrane-bound polyribosomal mRNAs from rat brain has shown several to be developmentally regulated [Hall & Lim (1981) Biochem. J. 196, 327-336]. Here we describe the isolation and characterization of cDNAs corresponding to two such brain mRNAs. One cDNA (M444) hybrid-selected a 0.95 kb mRNA directing the synthesis in vitro of a 21 kDa pI-6.3 polypeptide, which was processed in vitro by microsomal membranes. A second cDNA (M1622) hybridized to a 2.2 kb mRNA directing the synthesis of a 55 kDa pI-5.8 polypeptide. Both mRNAs were specific to membrane-bound polyribosomes. Restriction maps of the corresponding genomic DNA sequences are consistent with both being single copy. The two mRNAs were present in astrocytic and neuronal cultures, but not in liver or spleen or in neuroblastoma or glioma cells. The two mRNAs were differently regulated during brain development. In the developing forebrain there was a gradual and sustained increase in M444 mRNA during the first 3 weeks post partum, whereas M1622 mRNA appeared earlier and showed no further increase after day 10. In the cerebellum the developmental increase in M444 mRNA was biphasic. After a small initial increase there was a decrease in this mRNA at day 10, coincident with high amounts of M1622 mRNA. This was followed by a second, larger, increase in M444 mRNA, when amounts of M1622 mRNA were constant. The contrasting changes in these two mRNAs in the developing cerebellum are of particular interest, since they occur during an intensive period of cell proliferation, migration and altering neural connectivity. As these mRNAs are specific to differentiated neural tissue, they represent useful molecular markers for studying brain differentiation.

1987 ◽  
Vol 7 (8) ◽  
pp. 2838-2844
Author(s):  
M R Mowatt ◽  
C E Clayton

Trypanosoma brucei undergoes many morphological and biochemical changes during transformation from the bloodstream trypomastigote to the insect procyclic trypomastigote form. We cloned and determined the complete nucleotide sequence of a developmentally regulated cDNA. The corresponding mRNA was abundant in in vitro-cultivated procyclics but absent in bloodstream forms. The trypanosome genome contains eight genes homologous to this cDNA, arranged as four unlinked pairs of tandem repeats. The longest open reading frame of the cDNA predicts a protein of 15 kilodaltons, the central portion of which consists of 29 tandem glutamate-proline dipeptides. The repetitive region is preceded by an amino-terminal signal sequence and followed by a hydrophobic domain that could serve as a membrane anchor; the mRNA was found on membrane-bound polyribosomes. These results suggest that the protein is membrane associated.


1990 ◽  
Vol 10 (4) ◽  
pp. 1507-1515
Author(s):  
L F Liang ◽  
S M Chamow ◽  
J Dean

The zona pellucida surrounds all mammalian oocytes and plays a vital role at fertilization and in early development. The genes that code for two of the mouse zona proteins (ZP2 and ZP3) represent a developmentally regulated set of genes whose expression serves as markers of mouse oocyte growth and differentiation. We previously characterized the single-copy Zp-3 gene and showed that its expression is oocyte specific and restricted to a narrow window of oocyte development. We now define the Zp-2 gene transcript and show that it is coordinately expressed with Zp-3 only during the 2-week growth phase of oogenesis that occurs prior to ovulation. Like Zp-3, the expression of Zp-2 is restricted to oocytes, and, although not detectable in resting oocytes, both ZP2 and ZP3 transcripts accumulate to become very abundant messengers in 50-microns-diameter oocytes. Ovulated eggs contain ZP2 and ZP3 transcripts which are 200 nucleotides shorter than those found in growing oocytes and have an abundance of less than 5% of the peak levels. In an attempt to understand the molecular details associated with the developmentally regulated, tissue-specific gene expression of the zona genes, the Zp-2 genetic locus has been characterized and its 5' flanking sequences have been compared with those of Zp-3. Both genes contain three short (8- to 12-base-pair) DNA sequences of 80 to 88% identity located within 250 base pairs of their transcription start sites.


1984 ◽  
Vol 4 (11) ◽  
pp. 2396-2405
Author(s):  
R L Last ◽  
J B Stavenhagen ◽  
J L Woolford

Temperature-sensitive mutations in the genes RNA2 through RNA11 cause accumulation of intervening sequence containing precursor mRNAs in Saccharomyces cerevisiae. Three different plasmids have been isolated which complement both the temperature-sensitive lethality and precursor mRNA accumulation when introduced into rna2, rna3, and rna11 mutant strains. The yeast sequences on these plasmids have been shown by Southern transfer hybridization and genetic mapping to be derived from the RNA2, RNA3, and RNA11 genomic loci. Part of the RNA2 gene is homologous to more than one region of the yeast genome, whereas the RNA3 and RNA11 genes are single copy. RNAs homologous to these loci have been identified by RNA transfer hybridization, and the specific RNAs which are associated with the Rna+ phenotype have been mapped. This was done by a combination of transcript mapping, subcloning, and in vitro mutagenesis. The transcripts are found to be enriched in polyadenylated RNA and are of very low abundance (0.01-0.001% polyadenylated RNA).


1986 ◽  
Vol 6 (10) ◽  
pp. 3433-3442
Author(s):  
L Thelander ◽  
P Berg

Mammalian ribonucleotide reductase consists of two nonidentical subunits, proteins M1 and M2, which are differentially regulated during the cell cycle. We have isolated expressible cDNA clones of both subunits from an Okayama-Berg cDNA library made with mRNA from hydroxyurea-resistant, M2 protein-overproducing mouse TA3 cells. Expression of M2 protein could be demonstrated by electron paramagnetic resonance spectroscopy after transfection of COS-7 monkey cells with the plasmid. Electrophoresis and blot analyses of the parent and hydroxyurea-resistant TA3 mRNA revealed two M2 transcripts, a major one of 2.1 kilobases and a minor one of about 1.6 kilobases. Restriction endonuclease mapping of the corresponding cDNAs indicated that the two mRNAs differed only in the length of the 3' untranslated ends. By contrast, there was only one mRNA corresponding to the M1 protein, and its mobility corresponded to about 3.1 kilobases. The hydroxyurea-resistant TA3 cells contained a 50- to 100-fold excess of the M2 mRNAs over that of the parent cells and a 10-fold excess of the M1 mRNA. However, a Southern blot analysis of the corresponding genomic DNA sequences showed that the M2 gene was amplified fivefold but the M1 gene was still single copy. The complete nucleotide sequence of the 2,111-base-pair-long M2 cDNA revealed an open reading frame coding for 390 amino acids, which corresponds to a molecular weight of 45,100. The mouse M2 protein sequence was quite homologous to the equivalent protein in the clam Spisula solidissima, while the homology to the smaller subunits of Epstein-Barr virus, herpes simplex virus type 2, and Escherichia coli ribonucleotide reductases were less pronounced.


1990 ◽  
Vol 267 (2) ◽  
pp. 517-525 ◽  
Author(s):  
E Manser ◽  
D Fernandez ◽  
L Loo ◽  
P Y Goh ◽  
C Monfries ◽  
...  

Carboxypeptidase E (CPE), which cleaves C-terminal amino acid residues and is involved in neuropeptide processing, is itself subject to intracellular processing. Human CPE cDNA was isolated and sequence comparisons were made with those of a previously isolated brain cDNA (M1622) encoding rat CPE and of other human carboxypeptidases (M and N). Human (2.5 kb) and rat (2.1 kb) CPE cDNAs approximated to the size of their respective mRNAs; additional sequences were located in putative 5′ and 3′ untranslated regions of human CPE mRNA. There is 79% sequence similarity between human and rat CPE cDNAs, with greater similarity (89%) over the coding region and short sections of the non-coding sequence. The predicted 476-amino acid-residue sequences of human and rat preproCPEs are highly conserved (96% identity), with lower degree of similarity of the N-terminal signal peptide (76%). Human CPE showed 51% and 43% sequence similarity to human CPN and CPM respectively, with discrete regions of divergence dispersed between the highly conserved mechanistically implicated regions. Antiserum generated from a fusion protein, synthesized in Escherichia coli from constructs of the human cDNA, recognized an approx. 50 kDa membrane protein and a smaller soluble protein in rat and human brain preparations, corresponding to the two forms of native CPE. Human CPE mRNA transcripts directed the synthesis in reticulocyte lysate of a 54 kDa translation product, which in the presence of dog pancreas microsomal membranes was co-translationally processed with cleavage, insertion into membranes and glycosylation. Three processed forms were generated, the largest (56 kDa) and smallest (52 kDa) being equally glycosylated. The membrane association of the processed translation products and of native brain membrane CPE, detected immunologically, was resistant to moderate alkali but not pH 11.5 extraction. These results are consistent with secondary-structure predictions that CPE is a peripheral membrane protein. The dissimilar regions of human carboxypeptidases may provide information on sequences responsible for their different cellular disposition.


2006 ◽  
Vol 26 (1) ◽  
pp. 293-302 ◽  
Author(s):  
Natali Froese ◽  
Michael Schwarzer ◽  
Ina Niedick ◽  
Ursula Frischmann ◽  
Mario Köster ◽  
...  

ABSTRACT NF-κB-repressing factor (NRF) is a transcriptional silencer protein that specifically counteracts the basal activity of several NF-κB-dependent promoters by direct binding to specific neighboring DNA sequences. In cell culture experiments, the reduction of NRF mRNA leads to a derepression of beta interferon, interleukin-8, and inducible nitric oxide synthase transcription. The X chromosome-located single-copy NRF gene is ubiquitously expressed and encodes a protein of 690 amino acids. The N-terminal part contains a nuclear localization signal, the DNA-binding domain, and the NF-κB-repressing domain, while the C-terminal part is responsible for double-stranded RNA binding and nucleolar localization. To study the function of NRF in a systemic context, transgenic mice lacking the NRF gene were created. Against predictions from in vitro experiments, mice with a deletion of the NRF gene are viable and have a phenotype that is indistinguishable from wild-type mice, even after challenge with different pathogens. The data hint towards an unexpected functional redundancy of NRF.


1984 ◽  
Vol 4 (12) ◽  
pp. 2643-2652
Author(s):  
D K Burns ◽  
B C Stark ◽  
M D Macklin ◽  
W Y Chooi

Ribosomal (r) proteins encoded by polyadenylated RNA were specifically precipitated in vitro from polysomes by using antibodies raised against characterized Drosophila melanogaster r proteins. The immuno-purified mRNA in the polysome complex was used to prepare cDNA with which to probe a D. melanogaster genomic library. Selected recombinant phages were used to hybrid select mRNAs, which were analyzed by in vitro translation. Three clones containing the genes for r proteins 7/8, S18, and L12 were positively identified by electrophoresis of the translation products in one-dimensional and two-dimensional polyacrylamide gels. Sequences encoding r proteins S18 and L12 were found to be present in the genome in single copies. In contrast, the polynucleotide containing the region encoding 7/8 may be repeated or may contain or be flanked by short repeated sequences. The sizes of mRNAs that hybridized to the recombinant clone containing 7/8 were significantly larger than would be expected from the molecular weight of protein 7/8, implying that there were unusually long 5' and 3' noncoding sequences. The mRNAs for r proteins S18 and L12 were however, only about 10% larger. In situ hybridizations to salivary gland polytene chromosomes, using the recombinant phage, revealed that the recombinant clone containing the gene for r protein 7/8 hybridized to 5D on the X chromosome; the recombinant clone containing the gene for S18 hybridized to 15B on the same chromosome, and the recombinant phage containing the gene for L12 hybridized to 62E on chromosome 3L. It is of interest that the genomic locations of all three r protein clones were within the chromosomal intervals known to contain the Minute mutations [M(1)0, M(1)30, and M(3)LS2]. Although each clone contained sequences specifying two to four proteins, none had more than one identifiable r protein gene, suggesting that different D. melanogaster r protein genes may not be closely linked.


1987 ◽  
Vol 7 (8) ◽  
pp. 2838-2844 ◽  
Author(s):  
M R Mowatt ◽  
C E Clayton

Trypanosoma brucei undergoes many morphological and biochemical changes during transformation from the bloodstream trypomastigote to the insect procyclic trypomastigote form. We cloned and determined the complete nucleotide sequence of a developmentally regulated cDNA. The corresponding mRNA was abundant in in vitro-cultivated procyclics but absent in bloodstream forms. The trypanosome genome contains eight genes homologous to this cDNA, arranged as four unlinked pairs of tandem repeats. The longest open reading frame of the cDNA predicts a protein of 15 kilodaltons, the central portion of which consists of 29 tandem glutamate-proline dipeptides. The repetitive region is preceded by an amino-terminal signal sequence and followed by a hydrophobic domain that could serve as a membrane anchor; the mRNA was found on membrane-bound polyribosomes. These results suggest that the protein is membrane associated.


1986 ◽  
Vol 6 (10) ◽  
pp. 3433-3442 ◽  
Author(s):  
L Thelander ◽  
P Berg

Mammalian ribonucleotide reductase consists of two nonidentical subunits, proteins M1 and M2, which are differentially regulated during the cell cycle. We have isolated expressible cDNA clones of both subunits from an Okayama-Berg cDNA library made with mRNA from hydroxyurea-resistant, M2 protein-overproducing mouse TA3 cells. Expression of M2 protein could be demonstrated by electron paramagnetic resonance spectroscopy after transfection of COS-7 monkey cells with the plasmid. Electrophoresis and blot analyses of the parent and hydroxyurea-resistant TA3 mRNA revealed two M2 transcripts, a major one of 2.1 kilobases and a minor one of about 1.6 kilobases. Restriction endonuclease mapping of the corresponding cDNAs indicated that the two mRNAs differed only in the length of the 3' untranslated ends. By contrast, there was only one mRNA corresponding to the M1 protein, and its mobility corresponded to about 3.1 kilobases. The hydroxyurea-resistant TA3 cells contained a 50- to 100-fold excess of the M2 mRNAs over that of the parent cells and a 10-fold excess of the M1 mRNA. However, a Southern blot analysis of the corresponding genomic DNA sequences showed that the M2 gene was amplified fivefold but the M1 gene was still single copy. The complete nucleotide sequence of the 2,111-base-pair-long M2 cDNA revealed an open reading frame coding for 390 amino acids, which corresponds to a molecular weight of 45,100. The mouse M2 protein sequence was quite homologous to the equivalent protein in the clam Spisula solidissima, while the homology to the smaller subunits of Epstein-Barr virus, herpes simplex virus type 2, and Escherichia coli ribonucleotide reductases were less pronounced.


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