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Functional analysis of a newly identified TAAT‐box of the rat insulin‐II gene promoter
Author(s) -
Leibiger Ingo B.,
Schwarz Thomas,
Leibiger Barbara,
Walther Reinhard
Publication year - 1995
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(95)00243-3
Subject(s) - gene , insulin , promoter , biology , microbiology and biotechnology , computational biology , chemistry , genetics , gene expression , endocrinology
Transcriptional regulation of insulin gene expression is achieved by an interplay of tissue‐specific and ubiquitous cis ‐ and trans ‐acting elements. E‐box like motifs and TAAT‐motifs were shown to play a crucial role in initiating insulin gene transcription. Studying the AT‐rich region of the rat insulin‐II promoter betwee nucleotides −212 and −196, we observed a base difference at −211, an adenosine instead of a cytidine, compared to the previously reported sequence (EMBL Accession No. J00748). Sequence analysis of promoter fragments from different rat strains showed that adenosine at position −211 represents the wild type (EMBL Accession No. X82162). This base exchange leads to the formation of an additional TAAT‐motif, i.e. TAAT3, at the complementary DNA strand directly upstream of the previously studied TAAT2 motif, formerly named CT‐2. Here we show that the newly identified motif TAAT3 is involved in (i) transcriptional control in vivo, (ii) in vitro DNA/protein interactions, and that (iii) TAAT1, TAAT2 and TAAT3 are binding sites for the homeodomain‐containing factor IPF‐1.