Upstream elements required for efficient transcription of a human U6 RNA gene resemble those of U1 and U2 genes even though a different polymerase is used.

Abstract

U6 small nuclear RNA is transcribed by a different polymerase than U1-U5 RNAs, likely to be RNA polymerase III. Transcription from human U6 gene deletion-substitution templates in a HeLa S100 extract delineated the 5' border of a control element lying between 67 and 43 bp upstream from the initiation site. This region matches the location of, and shows considerable sequence similarity with, the proximal control element of U1 and U2 RNA genes, which are transcribed by RNA polymerase II. Transfection of human 293 cells with 5'-flanking deletion-substitution mutants of a U6 maxigene revealed a dominant control element between 245 and 149 bp upstream of the transcription start site. An octamer motif was found in this region in an inverted orientation relative to that of the human U1 and U2 RNA gene enhancers but in the same orientation as a human U4 RNA gene, the transcript of which functions together with U6 RNA in a single small nuclear ribonucleoprotein (snRNP) particle. The human U2 gene enhancer joined to the U6 maxigene was able to functionally replace the U6 distal control element(s).

Evolution of Spliceosomal snRNA Genes in Metazoan Animals

“…They were manually compared with previously published sequence elements. We visually compared the MEME -patterns with the upstream elements in related species from the following literature sources: [26] (general motifs), [14,82,2,38] (human), [36,5] (chicken), [53] (insects), [77] (Bombyx mori), [81] (Strongylocentrotus purpuratus), [84] (Caenorhabditis elegans).…”

SV40-derived vectors provide effective transgene expression and inhibition of HIV-1 using constitutive, conditional,and pol III promoters

“…SV[U6]TAR uses the U6 snRNA promoter, which activates transcription by RNA polymerase III, and produces small RNAs that localize within the nucleus. 8,9 These vectors were compared to a more conventional rSV40 vector, in which the CMV-IEP drives expression of the polyTAR transgene constitutively.…”

“…Although the efficiency of polymeric TAR decoys in inhibiting HIV-1 has been reported to improve with increasing numbers of TAR inserts, 3 U6 promoter can only drive expression of very small RNAs. 8,9 It was therefore elected to evaluate U6-P + TAR 1 inhibition of HIV-1 as a measure of rSV40 utility in delivering pol III-driven transgene expression. The TAR 1 decoy delivered by SV[U6]TAR could potentially overcome the disadvantage of carrying a single TAR by concentrating that decoy in the nucleus, which is the location of its target, Tat, rather than diluting its effectiveness by distributing it throughout the entire cell.…”

“…One was a simple, single TAR sequence, driven by the U6 small nuclear RNA (snRNA) promoter. [8][9][10][11] The other was dual function construct (polyTAR) containing a string of 25 TAR sequence (TAR 25 ) followed by an antisense-tat sequence (A/tat). TAR decoys, whether single or polymeric, were designed to sequester HIV-1 Tat protein by recapitulating HIV-1 TAR RNA sequences; the A/tat is intended to block Tat translation from its mRNA.…”

Distinct regulatory mechanism of immunoglobulin gene transcription in epithelial cancer cells

“…However, Oct-1 is a ubiquitous transcription factor that has been implicated in the control of non-immune-associated gene expression by all cell types, such as the histone H2B gene and the genes for snRNA, U2 and U6. [28][29][30][31] Although the regulatory mechanism of Ig transcription in B cells is well known, it is not yet clear how the non-B-cell-derived Ig transcription is controlled and whether the regulatory mechanism is equivalent to that of B-cell-derived Ig. In this study, we first tested whether the transcription factors associated with B-lymphocyte-specific Ig gene expression were expressed in several non-B cancer cell lines.…”