บทคัดย่องานวิจัย

หมวดหมู่ : ฐานข้อมูลงานวิจัย

Positive and negative regulatory regions control the spatial distribution of polygalacturonase transcription in tomato fruit pericarp.

Montgomery, J.; Pollard, V.; Deikman, J.; Fischer, R. L.;

Plant Cell Year: 1993 Vol: 5 Issue: 9 Pages: 1049-1062 Ref: 67 ref.

1993

บทคัดย่อ

Positive and negative regulatory regions control the spatial distribution of polygalacturonase transcription in tomato fruit pericarp.

During fruit ripening, the activation of gene expression results in dramatic biochemical and physiological changes in the parenchymatous cells of the pericarp. The polygalacturonase (PG) gene, unlike many fruit ripening-induced genes, is not activated by the increase in ethylene hormone concentration associated with the onset of ripening. To investigate ethylene concentration-independent gene transcription in ripe tomato fruit, the expression of chimaeric PG promoter- beta -glucuronidase (GUS) reporter gene fusions was analysed in transgenic tomato plants. A 1.4 kb PG promoter directs ripening-regulated transcription in outer but not in inner pericarp cells, with a sharp boundary of PG promoter activity located midway through the pericarp. Promoter deletion analysis indicated that a minimum of three promoter regions influence the spatial regulation of PG transcription. A positive regulatory region from -231 to -134 promotes gene transcription in the outer pericarp of ripe fruit. A second positiv

e regulatory region from -806 to -443 extends gene activity to the inner pericarp. However, a negative regulatory region from -1411 to -1150 inhibits gene transcription in the inner pericarp. DNase I footprint analysis showed that nuclear proteins in unripe and ripe fruit interact with DNA sequences within each of these three regulatory regions. Thus, temporal and spatial control of PG transcription is mediated by the interaction of negative and positive regulatory promoter elements, resulting in gene activity in the outer but not the inner pericarp of ripe tomato fruit. The expression pattern of PG suggests that, although they are morphologically similar, there is a fundamental difference between the parenchymatous cells within the inner and outer pericarp.