title: Odd-paired controls frequency doubling inDrosophilasegmentation by altering the pair-rule gene regulatory network.
abstract: TheDrosophilaembryo transiently exhibits a double-segment periodicity, defined by the expression of seven 'pair-rule' genes, each in a pattern of seven stripes. At gastrulation, interactions between the pair-rule genes lead to frequency doubling and the patterning of 14 parasegment boundaries. In contrast to earlier stages ofDrosophilaanteroposterior patterning, this transition is not well understood. By carefully analysing the spatiotemporal dynamics of pair-rule gene expression, we demonstrate that frequency-doubling is precipitated by multiple coordinated changes to the network of regulatory interactions between the pair-rule genes. We identify the broadly expressed but temporally patterned transcription factor, Odd-paired (Opa/Zic), as the cause of these changes, and show that the patterning of the even-numbered parasegment boundaries relies on Opa-dependent regulatory interactions. Our findings indicate that the pair-rule gene regulatory network has a temporally modulated topology, permitting the pair-rule genes to play stage-specific patterning roles.
authors.affiliation: Laboratory for Development and Evolution, Department of Zoology, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Erik
authors.identifier: http://orcid.org/0000-0002-5588-796X
authors.initials: E
authors.lastname: Clark
authors.affiliation: Laboratory for Development and Evolution, Department of Zoology, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Michael
authors.identifier: http://orcid.org/0000-0003-0063-2297
authors.initials: M
authors.lastname: Akam
keywords: D. melanogaster; Odd-paired; Zic; computational biology; developmental biology; gene regulatory network; pair-rule genes; patterning; segmentation; stem cells; systems biology