The arabidopsis ACT7 actin gene is expressed in rapidly developing tissues and responds to several external stimuli.
ACT7 encodes one of the six distinct and ancient subclasses of actin protein in the complex Arabidopsis actin gene family. We determined the sequence and structure of the Arabidopsis thaliana ACT7 actin gene and investigated its tissue-specific expression and regulation. The ACT7 mRNA levels varied by 128-fold among several different tissues and organs. The highest levels of aCT7 mRNA were found in rapidly expanding vegetative organs, the lowest in pollen. A translational fusion with the 5' end of ACT 7 (1.9 kb) joined to the beta-glucuronidase reporter gene was strongly and preferentially expressed in all young, developing vegetative tissues of transgenic Arabidopsis plants. ACT7 was the only Arabidopsis actin gene strongly expressed in the hypocotyl and seed coat. Although no beta-glucuronidase expression was seen in developing ovules or immature seeds, strong expression was seen in dry seeds and immediately after imbibition in the entire seedling. ACT7 was the only Arabidopsis actin gene to respond strongly to auxin, other hormone treatments, light regime, and wounding, and may be the primary actin gene responding to external stimuli. The ACT7 promoter sequence contains a remarkable number of motifs with sequence similarity to putative phytohormone response elements.
McDowell
J M
JM
Department of Biology, University of North Carolina, Chapel Hill 27599, USA.
An
Y Q
YQ
Huang
S
S
McKinney
E C
EC
Meagher
R B
RB
D000199:Actins / Q000096:biosynthesis* / Q000235:genetics; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D001483:Base Sequence; D017931:DNA Primers; D005091:Exons; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D015723:Gene Library; D017343:Genes, Plant; D005982:Glutathione Transferase; D008969:Molecular Sequence Data; D005810:Multigene Family; D010937:Plant Growth Regulators / Q000494:pharmacology*; D016133:Polymerase Chain Reaction; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D016385:TATA Box; D014158:Transcription, Genetic / Q000187:drug effects
D000199:Actins; D017931:DNA Primers; D010937:Plant Growth Regulators; D011993:Recombinant Fusion Proteins; D005982:Glutathione Transferase