Heterogeneity of the 5′ terminus of hen ovalbumin messenger ribonucleic acid

Malek, Lawrence T.; Eschenfeldt, William H.; Munns, Theodore W.; Rhoads, Robert E.

doi:10.1093/nar/9.7.1657

Cited by 50 publications

(19 citation statements)

References 30 publications

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“…It is not clear whether the two closely spaced nuclease-resistant fragments observed in this experiment (Fig. 5) result from incomplete nuclease S1 digestion or if they reflect a true startsite microheterogeneity as observed in a number of other well-characterized systems (30,31).…”

Section: Discussionmentioning

confidence: 78%

Isolation and characterization of the rat tyrosine aminotransferase gene.

Shinomiya¹,

Scherer²,

Schmid³

et al. 1984

Proc. Natl. Acad. Sci. U.S.A.

118

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Tyrosine aminotransferase (TAT; L-tyrosine:2-oxoglutarate aminotransferase, EC 2.6.1.5) from rat liver is subject to glucocorticoid, cAMP, and developmental control. To study the underlying regulatory mechanisms, the TAT structural gene was isolated from a X bacteriophage rat DNA library. Heteroduplex analysis revealed that the 2.4-kilobase-long TAT mRNA is encoded by a gene that extends over 11 kilobases and is interrupted by 11 introns. To characterize the presumptive control region, the DNA sequence around the 5' end of the gene was determined and the start site of transcription was identified by nuclease S1 protection experiments. A short sequence homology in an equivalent position relative to the cap site was detected between TAT and tryptophan oxygenase, another glucocorticoid-controlled gene from rat liver. This sequence is related to the sequence 5' T-G-T-T-C-T 3' found in regions of the long terminal repeat of mouse mammary tumor virus, which has been shown to interact with the glucocorticoid receptor [Scheidereit, C., Geisse, J. A classical example for steroid hormone control is the induction of the enzymatic activities of both tyrosine aminotransferase (TAT; L-tyrosine:2-oxoglutarate aminotransferase, EC 2.6.1.5) and tryptophan oxygenase [TO; tryptophan 2,3-dioxygenase, L-tryptophan:oxygen 2,3-oxidoreductase (decyclizing), EC 1.13.11.11] in rat liver. The increase in activity of these two gluconeogenic enzymes after glucocorticoid stimulation results from an increased rate of enzyme synthesis (1-3), which derives from an increase in the amount of translatable mRNA (4-6). Apart from glucocorticoid induction, the activity of TAT is also inducible by cAMP (7,8). Since both hormonal controls for TAT are also operative in a number of established rat hepatoma cell lines, the hormonal induction of TAT in hepatoma cells has become an attractive model system to study regulated gene expression in mammalian cells (9).In addition to hormonal modulation, both TAT and TO activity are also under developmental control. While TAT enzyme activity appears around birth (10), TO enzyme activity can be detected around postnatal day 15 (11).By genetic and biochemical analysis of several albino lethal mutants of the mouse, a control region required for expression and inducibility of mouse TAT has been assigned to the region of the albino locus on chromosome 7 (12). In these mutants, the activity of several liver enzymes is affected. The basal level of TAT is severely decreased and the enzyme activity is no longer inducible by glucocorticoids, although the structural gene for TAT is still present (13).To study the complex control mechanisms operating on these two liver-specific genes at the molecular level, we have isolated the TAT and TO genes from the rat genome.. We have previously described the isolation and characterization of cDNA as well as genomic clones for TO (14). With these molecular clones as probes, some of us have shown that glucocorticoid induction of TO occurs at the transcriptional level (15). Simila...

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Section: Discussionmentioning

confidence: 78%

Isolation and characterization of the rat tyrosine aminotransferase gene.

Shinomiya¹,

Scherer²,

Schmid³

et al. 1984

Proc. Natl. Acad. Sci. U.S.A.

118

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“…Three major RNA products were observed, differing in size by 2 to 6 nucleotides. We do not know whether these differences are due to heterogeneous transcription starts observed in vivo (30) or to residual unpaired residues resistant to RNase A digestion.…”

Section: Methodsmentioning

confidence: 95%

Control of transcription initiation in vitro requires binding of a transcription factor to the distal promoter of the ovalbumin gene.

Pastorcic¹,

Wang²,

Elbrecht³

et al. 1986

Mol. Cell. Biol.

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We used a cell-free HeLa cell transcription system to identify and characterize transcription factors and the promoter elements that they recognize in RNA polymerase II-transcribed genes. Deletion of the region (-71 to -83) containing the GTCAAA direct repeat resulted in a marked decrease of specific transcription of the ovalbumin gene; transcription could be competed with DNA fragments containing this sequence. Furthermore, DNase I footprinting identified a protein-binding site including this direct repeat with crude extracts and one of the partially purified protein fractions required for transcription. We propose that a soluble factor activates transcription through binding to the direct repeat of GTCAAA sequence upstream from the ovalbumin gene.Recombinant DNA methodology and the techniques of gene transfer have facilitated the characterization of promoters for RNA polymerase II-transcribed genes. The efficiency of mutated promoters in directing accurate initiation has been tested in vivo and in vitro (1,2,10,32). These experiments suggested the existence of distinct promoter elements upstream from the initiation site of transcription. The TATA box, a highly conserved homology among mRNA coding genes and located at -24 to -32 base pairs from the initiation site, is essential for efficient and accurate initiation of most genes both in vivo and in vitro (2, 32). In addition, sequences upstream from the TATA box have been shown to be required in vivo (32) and in vitro (20,22,24,27,29,40,41) for efficient transcription of many eucaryotic genes. This is clearly the case for the ovalbumin gene in vivo (28). We previously showed that accurate initiation of the ovalbumin gene transcription in vitro requires the TATA homology (39, 42). We demonstrate here that sequences upstream from the TATA box are important for quantitative transcription of the ovalbumin gene in crude extracts from HeLa cells. This upstream promoter element is located approximately 80 base pairs from the cap site and includes a direct repeat of GTCAAA sequence. Since this region was originally defined by Benoist et al. (1) and Efstratiadis et al. (11) as the CAAT-box region, we tentatively designate the direct repeat sequence as the CAAT box for reference purposes.The requirement for a distal promoter element was initially indicated by 5' deletion mapping. To test whether a transcription factor interacts with this promoter element, we performed transcription competition assays and found that crucial sequences for the binding of a transcription factor include the CAAT box. We have shown previously by exonuclease footprinting that a protein which binds to this region of the ovalbumin gene is present in HeLa cell fractions (13). We now confirm and extend this footprinting analysis using DNase I with either crude nuclear extracts or the partially purified fractions (38) required for transcription in reconstituted systems. These results suggest that the upstream element delineated by the functional transcription assays is the specific binding site fo...

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“…In these cases several mRNAs are made from a single gene, but they differ by only a few bases in length. Some examples are the human alpha actin gene (27), the D. melanogaster myosin LC-2 gene (41), the adenovirus type 2 EIl gene (1), the simian virus 40 late genes (16,22,23), the polyomavirus late genes (17), the chicken ovalbumin gene (34), the chicken lysozyme gene (24), and the yeast Adh-I gene (3).…”

Section: Discussionmentioning

confidence: 99%

The Drosophila melanogaster actin 5C gene uses two transcription initiation sites and three polyadenylation sites to express multiple mRNA species.

Bond¹,

Davidson²

1986

Mol. Cell. Biol.

101

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At least six mRNAs are made from the Drosophila melanogaster act5C gene. We investigated the structures of these RNAs in detail and determined that they are heterogeneous at both their 5' and 3' ends. At the 5' end there were two nonhomologous leader exons which were alternately spliced to the remainder of the gene. These leader exons mapped to 1.7 and 0.7 kilobases, respectively, upstream of a common splice acceptor site which was eight base pairs 5' to the translation initiator AUG. Exon 1 is 147 bases in length, while exon 2 is 111 bases. A consensus TATA sequence was found roughly 30 base pairs upstream from exon 1, but none was found in the analogous position upstream of exon 2. The transcript length diversity arose principally from the use of three polyadenylation sites. This gave rise to RNA molecules with 3'-untranslated regions of roughly 375, 655, and 945 base pairs. With two start sites and three termination sites, this gene has the potential to produce six different transcripts. All six possible transcripts were present in whole fly mRNA. Transcripts containing the two different leader exons were found in roughly the same relative quantities through development. In contrast, the various 3' ends were differentially represented through development.

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Heterogeneity of the 5′ terminus of hen ovalbumin messenger ribonucleic acid

Cited by 50 publications

References 30 publications

Isolation and characterization of the rat tyrosine aminotransferase gene.

Isolation and characterization of the rat tyrosine aminotransferase gene.

Control of transcription initiation in vitro requires binding of a transcription factor to the distal promoter of the ovalbumin gene.

The Drosophila melanogaster actin 5C gene uses two transcription initiation sites and three polyadenylation sites to express multiple mRNA species.

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