BMB Rep. 2016; 49(10): 572-577  
Transcriptional activity of the short gastrulation primary enhancer in the ventral midline requires its early activity in the presumptive neurogenic ectoderm
Dong-Hyeon Shin & Joung-Woo Hong*
Graduate School of East-West Medical Science, Kyung Hee University, Yongin 17104, Korea
Correspondence to: Tel: +82-31-201-3853; Fax: +82-31-204-8119; E-mail:
Received: July 21, 2016; Revised: August 11, 2016; Accepted: August 30, 2016; Published online: October 31, 2016.
© Korean Society for Biochemistry and Molecular Biology. All rights reserved.

The short gastrulation (sog) shadow enhancer directs early and late sog expression in the neurogenic ectoderm and the ventral midline of the developing Drosophila embryo, respectively. Here, evidence is presented that the sog primary enhancer also has both activities, with the late enhancer activity dependent on the early activity. Computational analyses showed that the sog primary enhancer contains five Dorsal (Dl)-, four Zelda (Zld)-, three Bicoid (Bcd)-, and no Single-minded (Sim)-binding sites. In contrast to many ventral midline enhancers, the primary enhancer can direct lacZ expression in the ventral midline as well as in the neurogenic ectoderm without a canonical Simbinding site. Intriguingly, the impaired transcriptional synergy between Dl and either Zld or Bcd led to aberrant and abolished lacZ expression in the neurogenic ectoderm and in the ventral midline, respectively. These findings suggest that the two enhancer activities of the sog primary enhancer are functionally consolidated and geographically inseparable.
Keywords: Drosophila, Embryo, Primary enhancer, Shadow enhancer, short gastrulation

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