The Arabidopsis cytc-2 gene is regulated by the cooperative action of siteII and G-box motifs.

ELINA WELCHEN; IVANA VIOLA; RAÚL COMELLI; DANIEL GONZALEZ

Mar del Plata, Buenos Aires, Argentina.

Congreso; XLIII Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular, SAIB.; 2007

SAIB

<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:EN-GB;} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> <!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:EN-GB;} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> The Arabidopsis cytc-2 (At4g10040) gene has been shown to be upregulated in response to carbohydrates, cicloheximide and under stress conditions. Progressive deletions and base substitution analysis of the cytc-2 promoter region revealed a cooperative action between site II elements, G-box and ACGT motifs. While site II motifs regulate the magnitude of the response to different treatments and the basal expression in reproductive tissues, the main expression characteristics of the cytc-2 gene are dependent on an essential fragment (-189 to -139) containing a G-box and an ACGT motif. These motifs regulate the response to different effectors, such as light, carbohydrates, hormones, UV and environmental stress. By means of yeast one-hybrid screening we identified a group of transcription factors from the bZip and bHLH families (AtABF4, AtGBF1, AtGBF3, AtGBFlike, AtHLH080) that are able to bind to the cytc-2 G-box motif. Electrophoretic mobility shift assays using nuclear extracts indicated that the integrity of the region from -149 to -139 is required for efficient binding of proteins to the G-box motif, suggesting the existence of cooperative interactions. We conclude that site II motifs and the G-box, interacting with several transcription factors, are involved in determining specific aspects of the cytc-2 expression patterns. We conclude that site II motifs and the G-box interact with several transcription factors and are involved in determining specific aspects of the cytc-2 expression patterns.