Xenopus laevis TFIIIA gene 5' region and partial coding region, EMBL ID XLTF3A5.
Mol Cell Biol 1998 Jul;18(7):3811-8
Xenopus TFIIIA gene transcription is dependent on cis-element positioning
and chromatin structure.
Pfaff SL, Taylor WL Department of Molecular Physiology and Biophysics, Vanderbilt University,
Nashville, Tennessee 37232, USA.
The Xenopus TFIIIA gene is transcribed very efficiently in oocytes. In addition to a TATA element at -30, we show that from -425 to +7 the TFIIIA gene contains only two positive cis elements centered at -267 (element 1) and -230 (element 2). This arrangement of the cis elements in the TFIIIA gene is striking because these two elements are positioned very close to each other yet separated from the TATA element by approximately 190 nucleotides. We show that the 190-nucleotide spacing between the TATA element and the upstream cis elements (elements 1 and 2) is critical for efficient transcription of the gene in oocytes and that a nucleosome is positioned in this intervening region. This nucleosome may act positively on TFIIIA transcription in oocytes by placing transcription factors bound at elements 1 and 2 in a favorable position relative to the transcription complex at the TATA element.
TATA box located within 394-400 region relative to sequence start, center of nucleosome site placed approximately at 290.
Contributors: Sergey V. Lavryushev
Leader: Prof. N.A. Kolchanov
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