PT  - JOURNAL ARTICLE
AU  - Alexandra D. Buffry
AU  - Sebastian Kittelmann
AU  - Alistair P. McGregor
TI  - Characterisation of the role and regulation of <em>Ultrabithorax</em> in sculpting fine-scale leg morphology
AID  - 10.1101/2020.06.17.152918
DP  - 2020 Jan 01
TA  - bioRxiv
PG  - 2020.06.17.152918
4099  - http://biorxiv.org/content/early/2020/06/18/2020.06.17.152918.1.short
4100  - http://biorxiv.org/content/early/2020/06/18/2020.06.17.152918.1.full
AB  - Hox genes are expressed during embryogenesis and determine the regional identity of animal bodies along the antero-posterior axis. However, they also function post-embryonically to sculpt fine-scale morphology. To better understand how Hox genes are integrated into post-embryonic gene regulatory networks, we further analysed the role and regulation of Ultrabithorax (Ubx) during mesothoracic (T2) leg development in Drosophila melanogaster. Ubx represses leg trichomes in the proximal posterior region of the T2 femur (the so-called naked valley) and we found that it likely does so through activating the expression of microRNA-92a. We also identified a T2 leg enhancer of Ubx that recapitulates the temporal and regional activity of this Hox gene in these appendages. Analysis of motifs in this enhancer predicted that it is bound by Distal-less (Dll) and we found that knockdown of Dll results in the loss of trichomes on the T2 femur. This suggests that while Ubx activates microRNA-92a to repress trichomes in the naked valley region of the proximal femur, Dll may repress Ubx more distally to enable formation of trichomes. Taken together our results provide insights into how Ubx is integrated into a postembryonic gene regulatory network to determine fine-scale leg morphology.Competing Interest StatementThe authors have declared no competing interest.