Distinct genetic requirements for BX-C-mediated specification of abdominal denticles.

Background: Hox genes encode transcription factors playing important role in segment specific morphogenesis along the anterior posterior axis. Most work in the Hox field aimed at understanding the basis for specialised Hox functions, while little attention was given to Hox common function. In Drosophila, genes of the Bithorax complex [ Ultrabithorax ( Ubx), abdominalA ( abdA), and AbdominalB ( AbdB)] all promote abdominal identity. While Ubx and AbdA share extensive sequence conservation, AbdB is highly divergent, questioning how it can perform similar functions as Ubx and AbdA. Results: In this study, we investigate the genetic requirement for the specification of abdominal-type denticles by Ubx, AbdA, and AbdB. The impact of ectopic expression of Hox proteins in embryos mutant for Exd as well as of Wingless or Hedgehog signaling involved in intrasegmental patterning was analyzed. Results indicated that Ubx and AbdA do not require Exd, Wg, and Hh activity for specifying abdominal-type denticles, while AbdB does. Conclusions: Our results support that distinct regulatory mechanisms underlie Ubx/AbdA- and AbdB-mediated specification of abdominal-type denticles, highlighting distinct strategies for achieving a similar biological output. This suggests that common function performed by distinct paralogue Hox proteins may also rely on newly acquired property, instead of conserved/ancestral properties. Developmental Dynamics 243:192-200, 2014. © 2013 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]