Functional relationship among TATA sequences, gene induction and transcription initiation in theβ-galactosidase, LAC4, gene fromKluyveromyces lactis
✍ Scribed by Anna Grazia Ficca; Cornelius P. Hollenberg
- Publisher
- Springer-Verlag
- Year
- 1989
- Tongue
- English
- Weight
- 888 KB
- Volume
- 15
- Category
- Article
- ISSN
- 0172-8083
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✦ Synopsis
In the 5' non-coding region of the beta-galactosidase, LAC4, gene of Kluyveromyces lactis, three TATA-like sequences are present at -230, -170 and -142 from the ATG translation start site. By means of deletion mutations in the TATA region, at least two of these TATA sequences, those at -230 and -142, were shown to be required for normal gene expression. Evidence is presented for a functional hierarchy and cooperation between these TATA sequences. The deletion or a change in the position of the TATA sequences affects both beta-galactosidase induction and the location of RNA initiation sites. The TATA sequence at -230 alone is sufficient for correct gene induction when it is moved to a position 41 bp from the major RNA initiation sites located around -110; the -142 TATA alone contributes only partly to gene induction. We suggest a functional distinction between these two related regulatory sequences. This functional distinction might be established by sequence differences and/or targets of unlike specific DNA binding protein(s). A conformational analysis of the LAC4 promoter showed that under torsional stress the functional elements UAS, TATA boxes RNA initiation sites and ATG can be detected as P1-sensitive sites. Possible functions of DNA structural alterations on gene expression are discussed.