Naslov
Chromatin Remodelling and Transcriptional Regulation of the Yeast PHO8 Promoter in Comparison to the Coregulated PHO5 Promoter

Autori
Barbarić, Slobodan ; Muensterkoetter, Martin ; Hoerz, Wolfram

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Gene Transcription in Yeast / Hoerz, Wolfram - Albufeira : Albufeira, 2000

Skup
EuroConference on Signal Transduction, Transcriptional Regulation and Chromatin Structure

Mjesto i datum
Albufeira, Portugal, 02.07.2000. - 07.07.2000

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
transcriptional regulation; chromatin and gene regulation; Saccharomyces cerevisiae

Sažetak
Expression of the PHO8 and PHO5 genes which encode a non-specific alkaline and acid phosphatase, respectively, is regulated in response to the Pi concentration in the medium by the same transcription factors. Upon induction by phosphate starvation, both promoters undergo characteristic chromatin remodeling, yet the extent of remodeling at the PHO8 promoter is significantly lower than at PHO5. Despite the coordinate regulation of the two promoters the PHO8 promoter is almost 10 times weaker than PHO5. Here we show that of two Pho4 binding sites which had been previously mapped at the PHO8 promoter in vitro, only the high affinity one, UASp2, is functional in vivo. Activation of the PHO8 promoter is partially Pho2 dependent. However, unlike at PHO5, Pho4 can bind strongly to its binding site in the absence of Pho2 and remodel chromatin in a Pho2-independent manner. Replacement of the inactive UASp1 element by the UASp1 element from the PHO5 promoter results in more extensive chromatin remodeling and a concomitant two-fold increase in promoter activity. In contrast, replacement of the high affinity UASp2 site with the corresponding site from PHO5 precludes chromatin remodeling completely and as a consequence promoter activation, despite efficient binding of Pho4 to this site. Deletion of the promoter region normally covered by nucleosomes -3 and -2 results in a two-fold increase in promoter activity further supporting a repressive role of these nucleosomes. These data show that there can be strong binding of Pho4 to a UAS element without any chromatin remodeling and promoter activation. The close correlation between promoter activity and the extent of chromatin disruption strongly suggests that the low level of PHO8 induction in comparison to PHO5 is partly due to the inability of Pho4 to achieve complete chromatin remodeling at this promoter.

Izvorni jezik
Engleski

Znanstvena područja
Prehrambena tehnologija

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