scholarly journals In Yeast, the 3′ Untranslated Region or the Presequence ofATM1 Is Required for the Exclusive Localization of Its mRNA to the Vicinity of Mitochondria

2000 ◽  
Vol 20 (21) ◽  
pp. 7881-7892 ◽  
Author(s):  
M. Corral-Debrinski ◽  
C. Blugeon ◽  
C. Jacq
Keyword(s):  
Untranslated Region ◽  
Mrna Localization ◽  
Rna Localization ◽  
Yeast Cells ◽  
Mitochondrial Proteins ◽  
Coding Region ◽  
Gene Encoding ◽  
Mitochondrial Inner Membrane ◽  
Biochemical Analyses ◽  
Reporter Mrna

ABSTRACT We isolated mitochondria from Saccharomyces cerevisiaeto selectively study polysomes bound to the mitochondrial surface. The distribution of several mRNAs coding for mitochondrial proteins was examined in free and mitochondrion-bound polysomes. Some mRNAs exclusively localize to mitochondrion-bound polysomes, such as the ones coding for Atm1p, Cox10p, Tim44p, Atp2p, and Cot1p. In contrast, mRNAs encoding Cox6p, Cox5a, Aac1p, and Mir1p are found enriched in free cytoplasmic polysome fractions. Aac1p and Mir1p are transporters that lack cleavable presequences. Sequences required for mRNA asymmetric subcellular distribution were determined by analyzing the localization of reporter mRNAs containing the presequence coding region and/or the 3′-untranslated region (3′UTR) of ATM1, a gene encoding an ABC transporter of the mitochondrial inner membrane. Biochemical analyses of mitochondrion-bound polysomes and direct visualization of RNA localization in living yeast cells allowed us to demonstrate that either the presequence coding region or the 3′UTR ofATM1 is sufficient to allow the reporter mRNA to localize to the vicinity of the mitochondrion, independently of its translation. These data demonstrate that mRNA localization is one of the mechanisms used, in yeast, for segregating mitochondrial proteins.

scholarly journals Translational efficiency is regulated by the length of the 3' untranslated region.

1996 ◽  
Vol 16 (1) ◽  
pp. 146-156 ◽  
Author(s):  
R L Tanguay ◽  
D R Gallie
Keyword(s):  
Cho Cells ◽  
Posttranscriptional Regulation ◽  
Untranslated Region ◽  
Stop Codon ◽  
Chinese Hamster ◽  
Firefly Luciferase ◽  
Translational Efficiency ◽  
Coding Region ◽  
The Stability ◽  
Reporter Mrna

All polyadenylated mRNAs contain sequence of variable length between the coding region and the poly(A) tail. Little has been done to establish what role the length of the 3' untranslated region (3'UTR) plays in posttranscriptional regulation. Using firefly luciferase (luc) reporter mRNA in transiently transfected Chinese hamster ovary (CHO) cells, we observed that the addition of a poly(A) tail increased expression 97-fold when the length of the 3'UTR was 19 bases but that its stimulatory effect was only 2.3-fold when the length of the 3'UTR was increased to 156 bases. The effect of the luc 3'UTR on poly(A) tail function was orientation independent, suggesting that its length and not its primary sequence was the important factor. Increasing the length of the 3'UTR increased expression from poly(A)- mRNA but had little effect on poly(A)+ mRNA. To examine the effect of length on translational efficiency and mRNA stability, a 20-base sequence was introduced and reiterated downstream of the luc stop codon to generate a nested set of constructs in which the length of the 3'UTR increased from 4 to 104 bases. For poly(A)- reporter mRNA, translational efficiency in CHO cells increased 38-fold as the length of the 3'UTR increased from 4 to 104 bases. Increasing the length of the 3'UTR beyond 104 bases increased expression even further. Increasing the length of the 3'UTR also resulted in a 2.5-fold stabilization of the reporter mRNA. For poly(A)+ mRNA, the translational efficiency and mRNA half-life increased only marginally as the length of the 3'UTR increased from 27 to 161 bases. However, positioning the poly(A) tail only 7 bases downstream of the stop codon resulted in a 39-fold reduction in the rate of translation relative to a construct with a 27-base 3'UTR, which may be a consequence of the poly(A) tail-poly(A)-binding protein complex functioning as a steric block to translocating ribosomes as they approached the termination codon. The optimal length of the 3' noncoding region for maximal poly(A) tail-mediated stimulation of translation is approximately 27 bases. These data suggest that the length of the 3'UTR plays an important role in determining both the translational efficiency and the stability of an mRNA.

scholarly journals An eleven nucleotide section of the 3′-untranslated region is required for perinuclear localization of rat metallothionein-1 mRNA

2005 ◽  
Vol 387 (2) ◽  
pp. 419-428 ◽  
Author(s):  
David NURY ◽  
Hervé CHABANON ◽  
Marilyne LEVADOUX-MARTIN ◽  
John HESKETH
Keyword(s):  
Metal Binding ◽  
Untranslated Region ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Mrna Localization ◽  
Coding Region ◽  
Ovary Cells ◽  
Structural Context ◽  
Deletion Mutagenesis ◽  
Localization Signal

Localization of mRNAs provides a novel mechanism for synthesis of proteins close to their site of function. MT1 (metallothionein-1) is a small, metal-binding protein that is largely cytoplasmic but which can be found in the nucleus. The localization of rat MT1 requires the perinuclear localization of its mRNA by a mechanism dependent on the 3′-UTR (3′-untranslated region). The present study investigates the nature of this mRNA localization signal using Chinese-hamster ovary cells transfected with gene constructs in which either MT1 or the globin coding region is linked to different sequences from the MT1 3′-UTR. Deletion, mutagenesis and antisense oligonucleotide approaches indicate that nt 45–76 of the 3′-UTR, in particular nt 66–76, are required for the localization of either MT1 mRNA or chimaeric transcripts in which a β-globin coding region is linked to sequences from the MT1 3′-UTR. This section of the 3′-UTR contains a CACC repeat. Two mutations that are predicted to alter the secondary structure of this region also impair localization. Our hypothesis is that the perinuclear localization signal in MT1 mRNA is formed by a combination of the CACC repeat and its structural context.

scholarly journals The Role of the 3′ Untranslated Region in mRNA Sorting to the Vicinity of Mitochondria Is Conserved from Yeast to Human Cells

2003 ◽  
Vol 14 (9) ◽  
pp. 3848-3856 ◽  
Author(s):  
J. Sylvestre ◽  
A. Margeot ◽  
C. Jacq ◽  
G. Dujardin ◽  
M. Corral-Debrinski
Keyword(s):  
Untranslated Region ◽  
Dna Microarrays ◽  
Human Cells ◽  
Mitochondrial Proteins ◽  
Yeast Mitochondria ◽  
Recognition Mechanism ◽  
Respiratory Capacity ◽  
Mitochondrial Inner Membrane ◽  
Similar Association

We recently demonstrated, using yeast DNA microarrays, that mRNAs of polysomes that coisolate with mitochondria code for a subset of mitochondrial proteins. The majority of these mRNAs encode proteins of prokaryotic origin. Herein, we show that a similar association occurs between polysomes and mitochondria in human cells. To determine whether mRNA transport machinery is conserved from yeast to human cells, we examined the subcellular localization of human OXA1 mRNA in yeast. Oxa1p is a key component in the biogenesis of mitochondrial inner membrane and is conserved from bacteria to eukaryotic organelles. The expression of human OXA1 cDNA partially restores the respiratory capacity of yeast oxa1– cells. In this study, we demonstrate that 1) OXA1 mRNAs are remarkably enriched in mitochondrion-bound polysomes purified from yeast and human cells; 2) the presence of the human OXA1 3′ untranslated region (UTR) is required for the function of the human Oxa1p inside yeast mitochondria; and 3) the accurate sorting of the human OXA1 mRNA to the vicinity of yeast mitochondria is due to the recognition by yeast proteins of the human 3′ UTR. Therefore, it seems that the recognition mechanism of OXA1 3′ UTR is conserved throughout evolution and is necessary for Oxa1p function.

scholarly journals The half-life of c-myc mRNA in growing and serum-stimulated cells: influence of the coding and 3' untranslated regions and role of ribosome translocation.

1994 ◽  
Vol 14 (3) ◽  
pp. 2119-2128 ◽  
Author(s):  
D J Herrick ◽  
J Ross
Keyword(s):  
Hela Cells ◽  
Half Life ◽  
Untranslated Region ◽  
Stop Codon ◽  
Beta Globin ◽  
Coding Region ◽  
3T3 Cells ◽  
Globin Mrna ◽  
Gene Encoding ◽  
Sequence Elements

c-myc mRNA contains at least two discrete sequence elements that account for its short half-life, one in the 3' untranslated region and the other in the carboxy-terminal coding region (coding-region determinant). To investigate the function of each determinant, one or both were fused in frame to portions of a gene encoding long-lived beta-globin mRNA. Each chimeric gene was stably transfected into HeLa and NIH 3T3 cells and was transcribed from a constitutive cytomegalovirus promoter or from a serum-regulated c-fos promoter, respectively. The steady-state levels of the chimeric mRNAs in exponentially growing HeLa cells were compared, and their half-lives were measured by two independent methods: (i) in actinomycin D-treated HeLa cells and (ii) after serum addition to starved 3T3 cells. By each method, mRNAs containing either instability determinant were less stable than beta-globin mRNA. mRNA containing only the c-myc 3' untranslated region was not significantly more stable than mRNA with both determinants. In a cell-free mRNA decay system containing polysomes from transfected HeLa cells, mRNA containing the coding-region determinant was destabilized by addition of a specific RNA competitor, whereas mRNA containing only the 3' untranslated region was unaffected. When a stop codon was inserted upstream of the coding-region determinant, the chimeric mRNA was stabilized approximately twofold. These and other data suggest that degradation involving the coding-region determinant occurs most efficiently when ribosomes are translating the determinant.

scholarly journals The G-Protein α-Subunit GasC Plays a Major Role in Germination in the Dimorphic FungusPenicillium marneffei

Genetics ◽  
2003 ◽  
Vol 164 (2) ◽  
pp. 487-499 ◽  
Author(s):  
Sophie Zuber ◽  
Michael J Hynes ◽  
Alex Andrianopoulos
Keyword(s):  
G Protein ◽  
Germination Rate ◽  
Yeast Cells ◽  
Class Iii ◽  
Temperature Dependent ◽  
Gene Encoding ◽  
Α Subunit ◽  
G Protein Α Subunit ◽  
Opportunistic Human Pathogen

AbstractThe opportunistic human pathogen Penicillium marneffei exhibits a temperature-dependent dimorphic switch. At 25°, multinucleate, septate hyphae that can undergo differentiation to produce asexual spores (conidia) are produced. At 37° hyphae undergo arthroconidiation to produce uninucleate yeast cells that divide by fission. This work describes the cloning of the P. marneffei gasC gene encoding a G-protein α-subunit that shows high homology to members of the class III fungal Gα-subunits. Characterization of a ΔgasC mutant and strains carrying a dominant-activating gasCG45R or a dominant-interfering gasCG207R allele show that GasC is a crucial regulator of germination. A ΔgasC mutant is severely delayed in germination, whereas strains carrying a dominant-activating gasCG45R allele show a significantly accelerated germination rate. Additionally, GasC signaling positively affects the production of the red pigment by P. marneffei at 25° and negatively affects the onset of conidiation and the conidial yield, showing that GasC function overlaps with functions of the previously described Gα-subunit GasA. In contrast to the S. cerevisiae ortholog Gpa2, our data indicate that GasC is not involved in carbon or nitrogen source sensing and plays no major role in either hyphal or yeast growth or in the switch between these two forms.

Structure and expression of canary myc family genes

1991 ◽  
Vol 11 (3) ◽  
pp. 1770-1776
Author(s):  
R G Collum ◽  
D F Clayton ◽  
F W Alt
Keyword(s):  
Untranslated Region ◽  
Untranslated Regions ◽  
Coding Region ◽  
Protein Coding ◽  
Coding Regions ◽  
Neuronal Precursors ◽  
Myc Gene ◽  
Mature Neurons

We found that the canary N-myc gene is highly related to mammalian N-myc genes in both the protein-coding region and the long 3' untranslated region. Examined coding regions of the canary c-myc gene were also highly related to their mammalian counterparts, but in contrast to N-myc, the canary and mammalian c-myc genes were quite divergent in their 3' untranslated regions. We readily detected N-myc and c-myc expression in the adult canary brain and found N-myc expression both at sites of proliferating neuronal precursors and in mature neurons.

Ypsilon Schachtel, aDrosophilaY-box protein, acts antagonistically to Orb in theoskarmRNA localization and translation pathway

Development ◽  
2002 ◽  
Vol 129 (1) ◽  
pp. 197-209 ◽  
Author(s):  
Jennifer H. Mansfield ◽  
James E. Wilhelm ◽  
Tulle Hazelrigg
Keyword(s):  
Subcellular Localization ◽  
Essential Role ◽  
Genetic Interaction ◽  
Mrna Localization ◽  
Rna Localization ◽  
Essential Step ◽  
Positive Regulator ◽  
Body Patterning ◽  
Translational Regulators

Subcellular localization of mRNAs within the Drosophila oocyte is an essential step in body patterning. Yps, a Drosophila Y-box protein, is a component of an ovarian ribonucleoprotein complex that also contains Exu, a protein that plays an essential role in mRNA localization. Y-box proteins are known translational regulators, suggesting that this complex might regulate translation as well as mRNA localization. Here we examine the role of the yps gene in these events. We show that yps interacts genetically with orb, a positive regulator of oskar mRNA localization and translation. The nature of the genetic interaction indicates that yps acts antagonistically to orb. We demonstrate that Orb protein is physically associated with both the Yps and Exu proteins, and that this interaction is mediated by RNA. We propose a model wherein Yps and Orb bind competitively to oskar mRNA with opposite effects on translation and RNA localization.

Cap-dependent and cap-independent translation by internal initiation of mRNAs in cell extracts prepared from Saccharomyces cerevisiae

1994 ◽  
Vol 14 (11) ◽  
pp. 7322-7330 ◽  
Author(s):  
N Iizuka ◽  
L Najita ◽  
A Franzusoff ◽  
P Sarnow
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Yeast Cells ◽  
In Vitro Translation ◽  
Translation System ◽  
Translational Efficiency ◽  
Coding Region ◽  
Initiation Mechanism ◽  
Noncoding Regions ◽  
Cell Extracts ◽  
Independent Translation

Translation extracts were prepared from various strains of Saccharomyces cerevisiae. The translation of mRNA molecules in these extracts were cooperatively enhanced by the presence of 5'-terminal cap structures and 3'-terminal poly(A) sequences. These cooperative effects could not be observed in other translation systems such as those prepared from rabbit reticulocytes, wheat germ, and human HeLa cells. Because the yeast translation system mimicked the effects of the cap structure and poly(A) tail on translational efficiency seen in vivo, this system was used to study cap-dependent and cap-independent translation of viral and cellular mRNA molecules. Both the 5' noncoding regions of hepatitis C virus and those of coxsackievirus B1 conferred cap-independent translation to a reporter coding region during translation in the yeast extracts; thus, the yeast translational apparatus is capable of initiating cap-independent translation. Although the translation of most yeast mRNAs was cap dependent, the unusually long 5' noncoding regions of mRNAs encoding cellular transcription factors TFIID and HAP4 were shown to mediate cap-independent translation in these extracts. Furthermore, both TFIID and HAP4 5' noncoding regions mediated translation of a second cistron when placed into the intercistronic spacer region of a dicistronic mRNA, indicating that these leader sequences can initiate translation by an internal ribosome binding mechanism in this in vitro translation system. This finding raises the possibility that an internal translation initiation mechanism exists in yeast cells for regulated translation of endogenous mRNAs.

scholarly journals Long-range RNA interaction of two sequence elements required for endonucleolytic cleavage of human insulin-like growth factor II mRNAs.

1995 ◽  
Vol 15 (1) ◽  
pp. 235-245 ◽  
Author(s):  
W Scheper ◽  
D Meinsma ◽  
P E Holthuizen ◽  
J S Sussenbach
Keyword(s):  
Growth Factor ◽  
Long Range ◽  
Cleavage Site ◽  
Untranslated Region ◽  
Cleavage Product ◽  
Coding Region ◽  
Endonucleolytic Cleavage ◽  
Factor Ii ◽  
Sequence Elements ◽  
Rna Interaction

Human insulin-like growth factor II (IGF-II) mRNAs are subject to site-specific endonucleolytic cleavage in the 3' untranslated region, leading to an unstable 5' cleavage product containing the IGF-II coding region and a very stable 3' cleavage product of 1.8 kb. This endonucleolytic cleavage is most probably the first and rate-limiting step in degradation of IGF-II mRNAs. Two sequence elements within the 3' untranslated region are required for cleavage: element I, located approximately 2 kb upstream of the cleavage site, and element II, encompassing the cleavage site itself. We have identified a stable double-stranded RNA stem structure (delta G = -100 kcal/mol [418.4 kJ/mol]) that can be formed between element I and a region downstream of the cleavage site in element II. This structure is conserved among human, rat, and mouse mRNAs. Detailed analysis of the requirements for cleavage shows that the relative position of the elements is not essential for cleavage. Furthermore, the distance between the coding region and the cleavage site does not affect the cleavage reaction. Mutational analysis of the long-range RNA-RNA interaction shows that not only the double-stranded character but also the sequence of the stable RNA stem is important for cleavage.

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