Disease relevance of RpIII128

• Hepatitis B virus X protein induces RNA polymerase III-dependent gene transcription and increases cellular TATA-binding protein by activating the Ras signaling pathway [1].

High impact information on RpIII128

• The DNase I sensitivity of Xenopus laevis genes transcribed by RNA polymerase III [2].
• The TATA box sequence in eukaryotes is located about 25 bp upstream of many genes transcribed by RNA polymerase II (Pol II) and some genes transcribed by RNA polymerase III (Pol III) [3].
• Total DNAs from various animals were transcribed in vitro in a HeLa cell extract, and it was found that one to several discrete RNAs were transcribed by RNA polymerase III [4].
• Experiments with mammalian transcription extracts have led to the proposal that the La protein is required for multiple rounds of transcription by RNA polymerase III (E. Gottlieb and J. A. Steitz, EMBO J. 8:851-861, 1989; R. J. Maraia, D. J. Kenan, and J. D. Keene, Mol. Cell. Biol. 14:2147-2158, 1994) [5].
• Together, these results indicate that the TPA response in Drosophila cells stimulates specific transcription of RNA polymerase III genes by increasing the activity of the limiting transcription component, TFIIIB, and thereby increasing the number of functional transcription complexes [6].

Biological context of RpIII128

• These results are the first to demonstrate that a phorbol ester can induce RNA polymerase III gene expression [7].
• Antibodies directed against a fusion protein expressing 164 amino acids of the DmRP135 polypeptide cross-react with the second-largest subunit of RNA polymerase III of yeast and generate a distinct banding pattern on Drosophila polytene chromosomes distinguishable from that obtained with anti-RNA polymerase II antibodies [8].
• The hepatitis B virus X protein increases the cellular level of TATA-binding protein, which mediates transactivation of RNA polymerase III genes [9].
• This finding supports a recent model for eukaryotic tRNA gene transcription (Dingermann et al., 1983, J. Biol. Chem. 258, 10395-10402) that proposes transcription initiation is dependent on the ability of specific DNA sequences to sequester two RNA polymerase III transcription factors [10].
• The 3' flanking region contains a typical RNA polymerase III termination site of 6 consecutive T residues [11].

Anatomical context of RpIII128

• The identification of two antagonistic activities in a Xenopus oocyte extract that can modulate the in vitro transcription of RNA polymerase III genes [12].
• Biochemical studies have revealed La to be a promiscuous RNA-binding protein that appears to play a role in a variety of intracellular activities such as processing and/or transport of RNA polymerase III precursor transcripts and translational regulation from internal ribosome entry sites (IRES) [13].

Associations of RpIII128 with chemical compounds

• From the sedimentation behavior of the isolated active transcription complex and from its stability and transcriptional properties, we conclude that the 40% sucrose fraction contains an active transcription complex containing a cloned tRNA gene, RNA polymerase III, and the accessory protein factors required for transcription [14].
• However, our in vitro transcription study reveals that transcription from the human L1 promoter is highly sensitive to tagetitoxin, a selective inhibitor of RNA polymerase III (pol III), but insensitive to 1 micrograms/ml of alpha-amanitin, indicating that the human L1 promoter is pol III-dependent [15].
• A 129 base-pair domain at the 5' end of Bm1 shows 66% homology to a Drosophila valine transfer RNA gene; thus the 5' end of Bm1 may contain the split internal RNA polymerase III promoter that is characteristic of most transcribed tRNA-like retroposons [16].

Other interactions of RpIII128

• The intergenic distance between the 3' end of 128up mRNA and the 5' end of DmRP128 mRNA is only about 100 bp [17].
• RNA polymerase preparations of D. melanogaster were blotted and the second-largest subunits were identified with antibodies raised against polypeptides expressed from DmRP128 and DmRP135 [18].
• Most small nuclear RNAs (snRNAs) are synthesized by RNA polymerase II, but U6 snRNA is synthesized by RNA polymerase III [19].

References