Transcription of a silkworm tRNA<sub>c</sub><sup>Ala</sup>gene is directed by two AT-rich upstream sequence elements

Palida, Fakhruddin A.; Hale, Charles A.; Sprague, Karen U.

doi:10.1093/nar/21.25.5875

Cited by 27 publications

(25 citation statements)

References 54 publications

(42 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…(3,29,37) and has been found in the TFIIIB fraction of both systems (13,18,32,36). More compelling is our finding that the key functional elements of the tRNAIa upstream promoter are two AT-rich sequences that resemble TBP binding sites (TATA boxes) in class II promoters (24). The sequence upstream of tRNAAl'a genes differs markedly from that of the tRNAt'a upstream promoter (44).…”

Section: Methodssupporting

confidence: 55%

Silk gland-specific tRNA(Ala) genes interact more weakly than constitutive tRNA(Ala) genes with silkworm TFIIIB and polymerase III fractions.

Sullivan¹,

Young²,

White³

et al. 1994

Mol. Cell. Biol.

View full text Add to dashboard Cite

Constitutive and silk gland-specific tRNAAI" genes from silkworms have very different transcriptional properties in vitro. Typically, the constitutive type, which encodes tRNAVa, directs transcription much more efficiently than does the silk gland-specific type, which encodes tRNA,. We think that the inefficiency of the tRNAsAG gene underlies its capacity to be turned off in non-silk gland cells. An economical model is that the tRNASAGa promoter interacts poorly, relative to the tRNAA'a promoter, with one or more components of the basal transcription machinery. As a consequence, the tRNASAsG 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 tRNAA3la and tRNASAsG transcription rates. To determine whether a particular component of the silkworm transcription machinery is responsible for reduced complex formation on the tRNASAG gene, we measured competition by templates for defined fractions of this machinery.We find that the tRNAsG gene is greatly impaired, in comparison with the tRNAcA'a 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 tRNAAa and tRNAtIa genes. These results suggest that differential interaction with TFIIIB or

show abstract

Section: Methodssupporting

confidence: 55%

Silk gland-specific tRNA(Ala) genes interact more weakly than constitutive tRNA(Ala) genes with silkworm TFIIIB and polymerase III fractions.

Sullivan¹,

Young²,

White³

et al. 1994

Mol. Cell. Biol.

View full text Add to dashboard Cite

show abstract

Section: Methodsmentioning

confidence: 99%

“…Transcription reactions were performed as previously described (36). Each 20-l reaction mixture contained 5 l of oocyte extract, 2 ng of gene-containing plasmid, and nonspecific DNA (pUC13M [36]) to bring the total amount of DNA to 200 ng. Transcripts were detected autoradiographically after resolution by gel electrophoresis as described elsewhere (33).…”

Section: Methodsmentioning

confidence: 99%

“…To understand how these two genes are differentially regulated, we have investigated the basis of the transcriptional impairment of the tRNA SG Ala gene that is observed under typical in vitro conditions. Transcription of silkworm tRNA Ala genes is driven by both internal and external promoter elements (26,36,56). The critical difference between the tRNA C Ala and tRNA SG Ala genes is in the interaction of their 5Ј flanking promoter elements with the transcription factor complex, TFIIIB (47).…”

mentioning

confidence: 99%

“…On the other hand, silkworm Pol III promoters frequently contain AT-rich sequences that resemble TBP binding sites (36), although they vary in sequence and location with respect to the transcription initiation site. To determine whether the different abilities of tRNA C Ala and tRNA SG Ala promoters to interact with TFIIIB result from differences in their interaction with TBP, we analyzed the effects of promoter mutation on 12 12 TBP binding, on the stability of TFIIIB-promoter complexes, and on transcriptional activity.…”

mentioning

confidence: 99%

See 2 more Smart Citations

TATA-Binding Protein–TATA Interaction Is a Key Determinant of Differential Transcription of Silkworm Constitutive and Silk Gland-Specific tRNA^Ala Genes

Ouyang

Martinez

Young

et al. 2000

Molecular and Cellular Biology

Self Cite

View full text Add to dashboard Cite

We have investigated the contribution of specific TATA-binding protein (TBP)-TATA interactions to the promoter activity of a constitutively expressed silkworm tRNA C Ala gene and have also asked whether the lack of similar interactions accounts for the low promoter activity of a silk gland-specific tRNA SG Ala gene. We compared TBP binding, TFIIIB-promoter complex stability (measured by heparin resistance), and in vitro transcriptional activity in a series of mutant tRNA C Ala promoters and found that specific TBP-TATA contacts are important for TFIIIB-promoter interaction and for transcriptional activity. Although the wild-type tRNA C Ala promoter contains two functional TBP binding sequences that overlap, the tRNA SG Ala promoter lacks any TBP binding site in the corresponding region. This feature appears to account for the inefficiency of the tRNA SG Ala promoter since provision of either of the wild-type TATA sequences derived from the tRNA C Ala promoter confers robust transcriptional activity. Transcriptional impairment of the wild-type tRNA SG Ala gene is not due to reduced incorporation of TBP into transcription complexes since both the tRNA C Ala and tRNA SG Ala promoters form transcription complexes that contain the same amount of TBP. Thus, the deleterious consequences of the lack of appropriate TBP-TATA contacts in the tRNA SG Ala promoter must come from failure to incorporate some other essential transcription factor(s) or to stabilize the complete complex in an active conformation.The silkworm Bombyx mori provides a clear example of regulated tRNA gene expression. The demand for fibroin, the principal protein of silk, requires highly efficient transcription and translation of the fibroin gene in cells of the silk gland. Translational efficiency in these cells is maximized by the quantitative adaptation of the tRNA population to the composition of fibroin: 44% glycine, 29% alanine, and 12% serine (5,29,30,42). In the case of tRNA Ala , enrichment is achieved both by increasing the level of the constitutive type of tRNA Ala (tRNA C Ala ) and by synthesizing an additional, silk gland-specific, type (tRNA SG Ala ) (31,44). In vitro studies of representative tRNA C Ala and tRNA SG Ala genes have revealed transcription properties consistent with the patterns of tRNA C Ala and tRNA SG Ala accumulation in vivo. That is, in a variety of extracts from non-silk gland cells, the tRNA C Ala gene directs transcription much more efficiently than does the tRNA SG Ala gene, but in concentrated extracts from silk gland, the two genes are equally efficient (60). To understand how these two genes are differentially regulated, we have investigated the basis of the transcriptional impairment of the tRNA SG Ala gene that is observed under typical in vitro conditions. Transcription of silkworm tRNA Ala genes is driven by both internal and external promoter elements (26,36,56). The critical difference between the tRNA C Ala and tRNA SG Ala genes is in the interaction of their 5Ј flanking promoter elements with the transcri...

show abstract

Cloning of a putative Bombyx mori TFIIB‐related factor (BRF)

Martinez

Sprague

2003

Arch Insect Biochem Physiol

View full text Add to dashboard Cite

To identify the protein domains responsible for its conserved and specialized functions, putative TFIIB-Related Factor (BRF) from the silkworm (Bombyx mori) was compared with BRFs from other organisms. The Bombyx BRF coding region was assembled from three separate and overlapping cDNA fragments. Fragments encoding the middle portion and the 3' end were discovered in the Bombyx mori Genome Project "Silkbase" collection through sequence homology with human BRF1, and the fragment encoding the N-terminus was isolated in our laboratory using the 5' RACE method. Southern analysis showed that silkworm BRF is encoded by a single-copy gene. Bombyx BRF contains the following domains that have been noted in all other BRFs, and that are likely, therefore, to provide highly conserved functions: a zinc finger domain, an imperfect repeat, three "BRF Homology" domains, and an acidic domain at the C-terminus. As expected from the evolutionary relationships among insects and mammals, Bombyx BRF is more similar overall to Drosophila BRF (55% identical) than to human BRF1 (42% identical). Detailed examination of individual domains reveals a remarkable exception, however. Domain II of Bombyx BRF is more similar to its human counterpart than to Drosophila Domain II. This result indicates that Domain II has undergone unusual divergence in Drosophila, and suggests a structural basis for Drosophila BRF's unique pattern of interaction with other transcription factors.

show abstract

Transcription of a silkworm tRNA_c^Alagene is directed by two AT-rich upstream sequence elements

Cited by 27 publications

References 54 publications

Silk gland-specific tRNA(Ala) genes interact more weakly than constitutive tRNA(Ala) genes with silkworm TFIIIB and polymerase III fractions.

Silk gland-specific tRNA(Ala) genes interact more weakly than constitutive tRNA(Ala) genes with silkworm TFIIIB and polymerase III fractions.

TATA-Binding Protein–TATA Interaction Is a Key Determinant of Differential Transcription of Silkworm Constitutive and Silk Gland-Specific tRNA^Ala Genes

Cloning of a putative Bombyx mori TFIIB‐related factor (BRF)

Contact Info

Product

Resources

About

Transcription of a silkworm tRNAcAlagene is directed by two AT-rich upstream sequence elements

Cited by 27 publications

References 54 publications

Silk gland-specific tRNA(Ala) genes interact more weakly than constitutive tRNA(Ala) genes with silkworm TFIIIB and polymerase III fractions.

Silk gland-specific tRNA(Ala) genes interact more weakly than constitutive tRNA(Ala) genes with silkworm TFIIIB and polymerase III fractions.

TATA-Binding Protein–TATA Interaction Is a Key Determinant of Differential Transcription of Silkworm Constitutive and Silk Gland-Specific tRNAAla Genes

Cloning of a putative Bombyx mori TFIIB‐related factor (BRF)

Contact Info

Product

Resources

About

Transcription of a silkworm tRNA_c^Alagene is directed by two AT-rich upstream sequence elements

TATA-Binding Protein–TATA Interaction Is a Key Determinant of Differential Transcription of Silkworm Constitutive and Silk Gland-Specific tRNA^Ala Genes