Conservation of cis-regulatory elements in maize Dof01 promoter: a key regulator of the cold stress response

Abstract

Gene expression patterns are controlled by cis regulatory elements (CRE) present in promoters. To understand how CRE are responsible for transcriptional activity and shape the architecture of a promoter, it is necessary to identify them and associate them with specific responses. Comparative studies of Dof promoters have focused on analyzing these sequences in different species. However, it is unknown how CRE are conserved among different varieties of the same species. In this work, a comparative analysis of the Dof01 gene promoter sequences of five varieties of maize (Zea mays) (B73, Palomero Toluqueño, Teosinte, W22 and Mo17) was performed to understand the architecture of the Dof01 promoter. Sequence analysis shows that there is a 179 bp indel element that is present in the B73 Dof01 promoter but absent in the other four varieties. Also, highly conserved CRE can be identified and may be related to the response to low temperatures. Therefore, we analyzed the expression of the Dof01 gene in B73 and Palomero under conditions of stress from low (4°C) and high (42°C) temperature. The expression data considered that the Palomero Dof01 gene is over-expressed with respect to the control due to the cold response. This work is the first step for the functional characterization of the Dof01 gene promoter to identify the regulatory elements associated with the temperature stress response and obtain the minimum promoter necessary for transcriptional regulation.