A. Holk et al., REGULATION OF AN EMBRYOGENIC CARROT GENE (DC-2.15) AND IDENTIFICATIONOF ITS ACTIVE PROMOTER SITES, Plant molecular biology, 31(6), 1996, pp. 1153-1161
According to previous studies the expression of the gene DC 2.15 is in
duced in cultured carrot cells after a transfer to an auxin-free mediu
m, where somatic embryo development occurs. This embryogenic gene enco
des a proline-rich protein, which resembles proteins involved in auxin
-controlled developmental processes. To understand the mechanism under
lying the regulation of DC 2.15, an experimental approach has been emp
loyed which allows the direct identification of the DC 2.15 promoter s
tructure by applying PCR techniques. We demonstrate the presence of fi
ve distinct promoter sequences highly similar in structure, but slight
ly different in a common region of about 15 nucleotides, which contain
the binding site for the GATA factor originally found in the human HO
X gene. Activity of each promoter structure was assessed in developing
somatic embryos containing the specific sequence fused to the beta-gl
ucuronidase (GUS) reporter gene. For two of the five promoter structur
es a drastic increase in activity was registered during the torpedo st
age while the remaining three were inactive throughout the stages of s
omatic embryogenesis.