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The ancient subclasses of Arabidopsis ACTIN DEPOLYMERIZING FACTOR genes exhibit novel and differential expression
Author(s) -
Ruzicka Daniel R.,
Kandasamy Muthugapatti K.,
McKinney Elizabeth C.,
BurgosRivera Brunilis,
Meagher Richard B.
Publication year - 2007
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/j.1365-313x.2007.03257.x
Subject(s) - biology , arabidopsis , meristem , subclass , cytoplasm , arabidopsis thaliana , gene , pollen , gene expression , microbiology and biotechnology , genetics , botany , antibody , mutant
Summary The Actin Depolymerizing Factor ( ADF ) gene family of Arabidopsis thaliana encodes 11 functional protein isovariants in four ancient subclasses. We report the characterization of the tissue‐specific and developmental expression of all Arabidopsis ADF genes and the subcellular localization of several protein isovariants. The four subclasses exhibited distinct expression patterns as examined by qRT‐PCR and histochemical assays of a GUS reporter gene under the control of individual ADF regulatory sequences. Subclass I ADF s were expressed strongly and constitutively in all vegetative and reproductive tissues except pollen. Subclass II ADF s were expressed specifically in mature pollen and pollen tubes or root epidermal trichoblast cells and root hairs, and these patterns evolved from an ancient dual expression pattern comprised of both polar tip growth cell types, still observed in the monocot Oryza sativa . Subclass III ADF s were expressed weakly in vegetative tissues, but were strongest in fast growing and/or differentiating cells including callus, emerging leaves, and meristem regions. The single subclass IV ADF was constitutively expressed at moderate levels in all tissues, including pollen. Immunocytochemical analysis with subclass‐specific monoclonal antibodies demonstrated that subclass I isovariants localize to both the cytoplasm and the nucleus of leaf cells, while subclass II isovariants predominantly localize to the cytoplasm at the tip region of elongating root hairs and pollen tubes. The distinct expression patterns of the ADF subclasses support a model of ADF s co‐evolving with the ancient and divergent actin isovariants.