TFIIIR is an isoleucine tRNA

1994 ◽  
Vol 14 (6) ◽  
pp. 3588-3595
Author(s):  
H M Dunstan ◽  
L S Young ◽  
K U Sprague

Promoter-specific transcription by silkworm RNA polymerase III is dependent on several transcription factors (TFs) in addition to the polymerase itself. The activities present in silk gland nuclear extracts that are necessary to reconstitute transcription from class III genes in vitro have been resolved into several partially purified components. These include TFIIIR, which is unusual because it is composed of RNA. Here, we identify the RNA that provides TFIIIR activity as silkworm tRNA(IleIAU). This conclusion is based on copurification of tRNA(IleIAU) with TFIIIR activity, TFIIIR activity in synthetic tRNA(Ile), and hybrid selection of TFIIIR activity by antisense tRNA(IleIAU). We have tested the ability of a variety of other tRNAs to stimulate transcription and find that TFIIIR activity is highly specific to silkworm tRNA(IleIAU).

1994 ◽  
Vol 14 (6) ◽  
pp. 3588-3595 ◽  
Author(s):  
H M Dunstan ◽  
L S Young ◽  
K U Sprague

Promoter-specific transcription by silkworm RNA polymerase III is dependent on several transcription factors (TFs) in addition to the polymerase itself. The activities present in silk gland nuclear extracts that are necessary to reconstitute transcription from class III genes in vitro have been resolved into several partially purified components. These include TFIIIR, which is unusual because it is composed of RNA. Here, we identify the RNA that provides TFIIIR activity as silkworm tRNA(IleIAU). This conclusion is based on copurification of tRNA(IleIAU) with TFIIIR activity, TFIIIR activity in synthetic tRNA(Ile), and hybrid selection of TFIIIR activity by antisense tRNA(IleIAU). We have tested the ability of a variety of other tRNAs to stimulate transcription and find that TFIIIR activity is highly specific to silkworm tRNA(IleIAU).


1985 ◽  
Vol 5 (1) ◽  
pp. 40-45 ◽  
Author(s):  
A B Lassar ◽  
D H Hamer ◽  
R G Roeder

We have constructed recombinant simian virus 40 molecules containing Xenopus 5S RNA and tRNA genes. Recombinant minichromosomes containing these genes were isolated to study the interaction of RNA polymerase III transcription factors with these model chromatin templates. Minichromosomes containing a tRNAMet gene can be isolated in a stable complex with transcription factors (IIIB and IIIC) and are active in vitro templates for purified RNA polymerase III. In contrast, minichromosomes containing a 5S RNA gene are refractory to transcription by purified RNA polymerase III in either the absence or the presence of other factors.


1985 ◽  
Vol 5 (1) ◽  
pp. 40-45
Author(s):  
A B Lassar ◽  
D H Hamer ◽  
R G Roeder

We have constructed recombinant simian virus 40 molecules containing Xenopus 5S RNA and tRNA genes. Recombinant minichromosomes containing these genes were isolated to study the interaction of RNA polymerase III transcription factors with these model chromatin templates. Minichromosomes containing a tRNAMet gene can be isolated in a stable complex with transcription factors (IIIB and IIIC) and are active in vitro templates for purified RNA polymerase III. In contrast, minichromosomes containing a 5S RNA gene are refractory to transcription by purified RNA polymerase III in either the absence or the presence of other factors.


1993 ◽  
Vol 13 (5) ◽  
pp. 2655-2665 ◽  
Author(s):  
J G Howe ◽  
M D Shu

The Epstein-Barr virus-encoded small RNA (EBER) genes are transcribed by RNA polymerase III, but their transcription unit appears to contain both class II and class III promoter elements. One of these promoter element, a TATA-like box which we call the EBER TATA box, or ETAB, is located in a position typical for a class II TATA box but contains G/C residues in the normal T/A motif and a conserved thymidine doublet. Experiments using chloramphenicol acetyltransferase constructs and mutations in the TATA box of the adenovirus major late promoter showed that the ETAB promoter element does not substitute for a class II TATA box. However, when the ETAB promoter element sequence was changed to a class II TATA box consensus sequence, the EBER 2 gene was transcribed in vitro by both RNA polymerases II and III. From these results, we conclude that the ETAB promoter element is important for the exclusive transcription of the EBER 2 gene by RNA polymerase III.


1994 ◽  
Vol 14 (3) ◽  
pp. 1806-1814 ◽  
Author(s):  
H S Sullivan ◽  
L S Young ◽  
C N White ◽  
K U Sprague

Constitutive and silk gland-specific tRNA(Ala) genes from silkworms have very different transcriptional properties in vitro. Typically, the constitutive type, which encodes tRNA(AlaC), directs transcription much more efficiently than does the silk gland-specific type, which encodes tRNA(AlaSG). We think that the inefficiency of the tRNA(AlaCG) gene underlies its capacity to be turned off in non-silk gland cells. An economical model is that the tRNA(AlaSG) promoter interacts poorly, relative to the tRNA(AlaC) promoter, with one or more components of the basal transcription machinery. As a consequence, the tRNA(AlaSG) gene directs the formation of fewer transcription complexes or of complexes with reduced cycling ability. Here we show that the difference in the number of active transcription complexes accounts for the difference in tRNA(AlaC) and tRNA(AlaSG) transcription rates. To determine whether a particular component of the silkworm transcription machinery is responsible for reduced complex formation on the tRNA(AlaSG) gene, we measured competition by templates for defined fractions of this machinery. We find that the tRNA(AlaSG) gene is greatly impaired, in comparison with the tRNA(AlaC) gene, in competition for either TFIIIB or RNA polymerase III. Competition for each of these fractions is also strongly influenced by the nature of the 5' flanking sequence, the promoter element responsible for the distinctive transcriptional properties of tRNA(AlaSG) and tRNA(AlaC) genes. These results suggest that differential interaction with TFIIIB or RNA polymerase III is a critical functional distinction between these genes.


1996 ◽  
Vol 16 (12) ◽  
pp. 6841-6850 ◽  
Author(s):  
Z Wang ◽  
R G Roeder

An in vitro system reconstituted with highly purified RNA polymerase III, TFIIIC2, and TFIIIB has been used to identify two chromatographically distinct human RNA polymerase III transcription factors, TFIIIC1 and TFIIIC1', which are functionally equivalent to the previously defined TFIIIC1 (S. T. Yoshinaga, P. A. Boulanger, and A. J. Berk, Proc. Natl. Acad. Sci. USA 84:3585-3589, 1987). Interactions between TFIIIC2, TFIIIC1 (or TFIIIC1'), and the VA1 and tRNA1(Met) templates have been investigated by DNase I footprint analysis. Homogeneous TFIIIC2 alone shows only a weak footprint over the B-box region of the VA1 and tRNA1(Met) templates, whereas TFIIIC1 (or TFIIIC1') alone shows both a strong interaction over the downstream termination region and a very weak interaction near the A-box region. Importantly, when both factors are present simultaneously, TFIIIC1 (or TFIIIC1') dramatically enhances the level of TFIIIC2 binding and extends the footprint to a region that includes the A box. The downstream termination region is essential for this cooperative interaction between TFIIIC2 and TFIIIC1 (or TFIIIC1') on the VA1 and tRNA1(Met) templates and plays a role in the overall accuracy and efficiency of RNA polymerase III transcription.


1999 ◽  
Vol 19 (7) ◽  
pp. 4944-4952 ◽  
Author(s):  
Yng-Ju Hsieh ◽  
Zhengxin Wang ◽  
Robert Kovelman ◽  
Robert G. Roeder

ABSTRACT Human transcription factor IIIC (hTFIIIC) is a multisubunit complex that mediates transcription of class III genes through direct recognition of promoters (for tRNA and virus-associated RNA genes) or promoter-TFIIIA complexes (for the 5S RNA gene) and subsequent recruitment of TFIIIB and RNA polymerase III. We describe the cognate cDNA cloning and characterization of two subunits (hTFIIIC63 and hTFIIIC102) that are present within a DNA-binding subcomplex (TFIIIC2) of TFIIIC and are related in structure and function to two yeast TFIIIC subunits (yTFIIIC95 and yTFIIIC131) previously shown to interact, respectively, with the promoter (A box) and with a subunit of yeast TFIIIB. hTFIIIC63 and hTFIIIC102 show parallel in vitro interactions with the homologous human TFIIIB and RNA polymerase III components, as well as additional interactions that may facilitate both TFIIIB and RNA polymerase III recruitment. These include novel interactions of hTFIIIC63 with hTFIIIC102, with hTFIIIB90, and with hRPC62, in addition to the hTFIIIC102–hTFIIIB90 and hTFIIIB90–hRPC39 interactions that parallel the previously described interactions in yeast. As reported for yTFIIIC131, hTFIIIC102 contains acidic and basic regions, tetratricopeptide repeats (TPRs), and a helix-loop-helix domain, and mutagenesis studies have implicated the TPRs in interactions both with hTFIIIC63 and with hTFIIIB90. These observations further document conservation from yeast to human of the structure and function of the RNA polymerase III transcription machinery, but in addition, they provide new insights into the function of hTFIIIC and suggest direct involvement in recruitment of both TFIIIB and RNA polymerase III.


1994 ◽  
Vol 14 (3) ◽  
pp. 1806-1814
Author(s):  
H S Sullivan ◽  
L S Young ◽  
C N White ◽  
K U Sprague

Constitutive and silk gland-specific tRNA(Ala) genes from silkworms have very different transcriptional properties in vitro. Typically, the constitutive type, which encodes tRNA(AlaC), directs transcription much more efficiently than does the silk gland-specific type, which encodes tRNA(AlaSG). We think that the inefficiency of the tRNA(AlaCG) gene underlies its capacity to be turned off in non-silk gland cells. An economical model is that the tRNA(AlaSG) promoter interacts poorly, relative to the tRNA(AlaC) promoter, with one or more components of the basal transcription machinery. As a consequence, the tRNA(AlaSG) gene directs the formation of fewer transcription complexes or of complexes with reduced cycling ability. Here we show that the difference in the number of active transcription complexes accounts for the difference in tRNA(AlaC) and tRNA(AlaSG) transcription rates. To determine whether a particular component of the silkworm transcription machinery is responsible for reduced complex formation on the tRNA(AlaSG) gene, we measured competition by templates for defined fractions of this machinery. We find that the tRNA(AlaSG) gene is greatly impaired, in comparison with the tRNA(AlaC) gene, in competition for either TFIIIB or RNA polymerase III. Competition for each of these fractions is also strongly influenced by the nature of the 5' flanking sequence, the promoter element responsible for the distinctive transcriptional properties of tRNA(AlaSG) and tRNA(AlaC) genes. These results suggest that differential interaction with TFIIIB or RNA polymerase III is a critical functional distinction between these genes.


1999 ◽  
Vol 77 (5) ◽  
pp. 431-438 ◽  
Author(s):  
Jürgen Müller ◽  
Bernd-Joachim Benecke

Transcription of the human 7SL RNA gene by RNA polymerase III depends on the concerted action of transcription factors binding to the gene-internal and gene-external parts of its promoter. Here, we investigated which transcription factors interact with the human 7SL RNA gene promoter and which are required for transcription of the human 7SL RNA gene. A-box/B-box elements were previously identified in 5S RNA, tRNA, and virus associated RNA genes and are recognized by transcription factor IIIC (TFIIIC). The gene-internal promoter region of the human 7SL RNA gene shows only limited similarity to those elements. Nevertheless, competition experiments and the use of highly enriched factor preparations demonstrate that TFIIIC is required for human 7SL transcription. The gene-external part of the promoter includes an authentic cAMP-responsive element previously identified in various RNA polymerase II promoters. Here we demonstrate that members of the activating transcription factor/cyclic AMP-responsive element binding protein (ATF/CREB) transcription factor family bind specifically to this element in vitro. However, the human 7SL RNA gene is not regulated by cAMP in vivo. Furthermore, in vitro transcription of the gene does not depend on ATF/CREB transcription factors. It rather appears that a transcription factor with DNA-binding characteristics like ATF/CREB proteins but otherwise different properties is required for human 7SL RNA transcription.Key words: 7SL RNA, ATF, CRE, TFIIIC, RNA polymerase III.


1987 ◽  
Vol 7 (11) ◽  
pp. 3880-3887 ◽  
Author(s):  
L G Fradkin ◽  
S K Yoshinaga ◽  
A J Berk ◽  
A Dasgupta

The inhibition of transcription by RNA polymerase III in poliovirus-infected cells was studied. Experiments utilizing two different cell lines showed that the initiation step of transcription by RNA polymerase III was impaired by infection of these cells with the virus. The observed inhibition of transcription was not due to shut-off of host cell protein synthesis by poliovirus. Among four distinct components required for accurate transcription in vitro from cloned DNA templates, activities of RNA polymerase III and transcription factor TFIIIA were not significantly affected by virus infection. The activity of transcription factor TFIIIC, the limiting component required for transcription of RNA polymerase III genes, was severely inhibited in infected cells, whereas that of transcription factor TFIIIB was inhibited to a lesser extent. The sequence-specific DNA-binding of TFIIIC to the adenovirus VA1 gene internal promoter, however, was not altered by infection of cells with the virus. We conclude that (i) at least two transcription factors, TFIIIB and TFIIIC, are inhibited by infection of cells with poliovirus, (ii) inactivation of TFIIIC does not involve destruction of its DNA-binding domain, and (iii) sequence-specific DNA binding by TFIIIC may be necessary but is not sufficient for the formation of productive transcription complexes.


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