--- res: bibo_abstract: - The formation of the leaf vascular pattern has fascinated biologists for centuries. In the early leaf primordium, complex networks of procambial cells emerge from homogeneous subepidermal tissue. The molecular nature of the underlying positional information is unknown, but various lines of evidence implicate gradually restricted transport routes of the plant hormone auxin in defining sites of procambium formation. Here we show that a crucial member of the AtPIN family of auxin-efflux-associated proteins, AtPIN1, is expressed prior to pre-procambial and procambial cell fate markers in domains that become restricted toward sites of procambium formation. Subcellular AtPIN1 polarity indicates that auxin is directed to distinct "convergence points" in the epidermis, from where it defines the positions of major veins. Integrated polarities in all emerging veins indicate auxin drainage toward pre-existing veins, but veins display divergent polarities as they become connected at both ends. Auxin application and transport inhibition reveal that convergence point positioning and AtPIN1 expression domain dynamics are self-organizing, auxin-transport-dependent processes. We derive a model for self-regulated, reiterative patterning of all vein orders and postulate at its onset a common epidermal auxin-focusing mechanism for major-vein positioning and phyllotactic patterning.@eng bibo_authorlist: - foaf_Person: foaf_givenName: Enrico foaf_name: Scarpella, Enrico foaf_surname: Scarpella - foaf_Person: foaf_givenName: Danielle foaf_name: Marcos, Danielle foaf_surname: Marcos - foaf_Person: foaf_givenName: Jirí foaf_name: Jirí Friml foaf_surname: Friml foaf_workInfoHomepage: http://www.librecat.org/personId=4159519E-F248-11E8-B48F-1D18A9856A87 orcid: 0000-0002-8302-7596 - foaf_Person: foaf_givenName: Thomas foaf_name: Berleth, Thomas foaf_surname: Berleth bibo_doi: 10.1101/gad.1402406 bibo_issue: '8' bibo_volume: 20 dct_date: 2006^xs_gYear dct_publisher: Cold Spring Harbor Laboratory Press@ dct_title: Control of leaf vascular patterning by polar auxin transport@ ...