tRNA(IleIAU) (TFIIIR) plays an indirect role in silkworm class III transcription in vitro and inhibits low-frequency DNA cleavage.
tRNA(IleIAU) provides an activity, originally called TFIIIR, necessary to reconstitute transcription by silkworm RNA polymerase III in vitro from partially purified components. Here we report studies on the role of tRNA(IleIAU) in in vitro transcription. We show that tRNA(IleIAU) does not act positively but, rather, is required to prevent the action of a transcriptional inhibitor. We also show that the presence of tRNA(IleIAU) in transcription reaction mixtures prevents low-frequency DNA cleavage by the TFIIIB fraction. Studies on the mechanism of transcriptional inhibition suggest that this DNA cleavage could cause transcriptional inhibition through trans-inactivation of transcription machinery. The ability to block DNA cleavage, like the ability to facilitate transcription, is highly specific to silkworm tRNA(IleIAU).
Dunstan
H M
HM
Institute of Molecular Biology, University of Oregon, Eugene 97403.
Young
L S
LS
Sprague
K U
KU
D000818:Animals; D001483:Base Sequence; D012831:Bombyx / Q000235:genetics / Q000378:metabolism*; D004247:DNA / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism; D011088:DNA Ligases / Q000378:metabolism*; D005816:Genetic Complementation Test; D007700:Kinetics; D008969:Molecular Sequence Data; D012355:RNA, Transfer, Ile / Q000378:metabolism*; D015183:Restriction Mapping; D014157:Transcription Factors / Q000378:metabolism*; D019473:Transcription Factors, TFII; D014158:Transcription, Genetic
D012355:RNA, Transfer, Ile; D014157:Transcription Factors; D019473:Transcription Factors, TFII; C087356:transcription factor TFIIIR, Bombyx mori; D004247:DNA; D011088:DNA Ligases