title: Conserved and unique features of the homeologous maize Aux/IAA proteins ROOTLESS WITH UNDETECTABLE MERISTEM 1 and RUM1-like 1.
abstract: The maize (Zea mays L.) Aux/IAA protein RUM1 (ROOTLESS WITH UNDETECTABLE MERISTEM 1) is a key regulator of lateral and seminal root formation. An ancient maize genome duplication resulted in the emergence of its homeolog rum1-like1 (rul1), which displays 92% amino acid sequence identity with RUM1. Both, RUL1 and RUM1 exhibit the canonical four domain structure of Aux/IAA proteins. Moreover, both are localized to the nucleus, are instable and have similar short half-lives of ~23min. Moreover, RUL1 and RUM1 can be stabilized by specific mutations in the five amino acid degron sequence of domain II. In addition, proteins encoded by both genes interact in vivo with auxin response factors (ARFs) such as ZmARF25 and ZmARF34 in protoplasts. Although it was demonstrated that RUL1 and RUM1 can homo and heterodimerize in vivo, rul1 expression is independent of rum1. Moreover, on average rul1 expression is ~84-fold higher than rum1 in the 12 tested tissues and developmental stages, although the relative expression levels in different root tissues are very similar. While RUM1 and RUL1 display conserved biochemical properties, yeast-two-hybrid in combination with BiFC experiments identified a RUM1-associated protein 1 (RAP1) that specifically interacts with RUM1 but not with RUL1. This suggests that RUM1 and RUL1 are at least in part interwoven into different molecular networks.
authors.affiliation: Center for Molecular Cell and Systems Biology, College of Life Science, Fujian Agriculture & Forestry University, 350002 Fuzhou, China Crop Functional Genomics, Institute of Crop Science and Resource Conservation, University of Bonn, 53113 Bonn, Germany.
authors.forename: Yanxiang
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Crop Functional Genomics, Institute of Crop Science and Resource Conservation, University of Bonn, 53113 Bonn, Germany.
authors.forename: Caroline
authors.identifier: http://orcid.org/0000-0001-6699-9441
authors.initials: C
authors.lastname: Marcon
authors.affiliation: Crop Functional Genomics, Institute of Crop Science and Resource Conservation, University of Bonn, 53113 Bonn, Germany.
authors.forename: Huanhuan
authors.initials: H
authors.lastname: Tai
authors.affiliation: ZMBP, Center for Plant Molecular Biology, General Genetics, University of Tuebingen, 72076 Tuebingen, Germany.
authors.forename: Inga
authors.initials: I
authors.lastname: von Behrens
authors.affiliation: Crop Functional Genomics, Institute of Crop Science and Resource Conservation, University of Bonn, 53113 Bonn, Germany.
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Ludwig
authors.affiliation: Crop Functional Genomics, Institute of Crop Science and Resource Conservation, University of Bonn, 53113 Bonn, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Hey
authors.affiliation: ZMBP, Center for Plant Molecular Biology, Central Facilities, University of Tuebingen, 72076 Tuebingen, Germany.
authors.forename: Kenneth W
authors.initials: KW
authors.lastname: Berendzen
authors.affiliation: Crop Functional Genomics, Institute of Crop Science and Resource Conservation, University of Bonn, 53113 Bonn, Germany hochholdinger@uni-bonn.de.
authors.forename: Frank
authors.identifier: http://orcid.org/0000-0002-5155-0884
authors.initials: F
authors.lastname: Hochholdinger
mesh_terms: D000595:Amino Acid Sequence; D018506:Gene Expression Regulation, Plant; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment; D003313:Zea mays / Q000235:genetics* / Q000378:metabolism
chemical_list: D010940:Plant Proteins
keywords: Aux/IAA; RAP1; RUL1.; RUM1; maize; protein interaction; root