A. thaliana TRANSPARENT TESTA 1 is involved in seed coat development and defines the WIP subfamily of plant zinc finger proteins

Abstract

Seeds of the Arabidopsis thaliana transparent testa 1 mutant (tt1) appear yellow, due to the lack of condensed tannin pigments in the seed coat. The TT1 gene was isolated by reverse genetics using an En-1 transposon mutagenized A. thaliana population. TT1 gene expression was detected in developing ovules and young seeds only, and the gene was shown to encode a nuclear protein. Mutant seeds displayed altered morphology of the seed endothelium in which brown tannin pigments accumulate in wild-type plants, indicating that TT1 is involved in the differentiation of this cell layer. When overexpressed in transgenic A. thaliana plants, TT1 caused aberrant development and organ morphology. The protein contains a novel combination of two TFIIIA-type zinc finger motifs. Closely related motifs were detected in a number of putative proteins deduced from plant genomic and EST sequences. The new protein domain containing this type of zinc finger motifs was designated WIP, according to three strictly conserved amino acid residues. Our data indicate the existence of a small gene family in A. thaliana which is defined by the occurrence of the WIP domain. WIP genes may play important roles in regulating developmental processes, including the control of endothelium differentiation.

Endosperm and Nucellus Develop Antagonistically in Arabidopsis Seeds

“…To understand whether nucellus and endothelium engage in crosstalk to coordinate their development, we tested whether TT16 complements the tt16-1 mutant phenotypes when expressed in the endothelium, in the nucellus, or in both tissues. To specifically drive TT16 expression in the seed coat, we cloned the TT16 genomic sequence downstream of the TT1 promoter region (ProTT1:gTT16), a marker of endothelium development (Sagasser et al, 2002). We confirmed that the genomic sequence of TT16 does not change the expression pattern of the TT1 promoter by creating a ProTT1:gTT16-GUS line (Supplemental Figure 8).…”

Fruit Indehiscence Caused by Enhanced Expression of NO TRANSMITTING TRACT in Arabidopsis thaliana

“…1G). AT3G57670 consists of two exons and encodes a C2H2/C2HC-type zinc finger protein (Englbrecht et al, 2004;Sagasser et al, 2002). This gene was known as NO TRANSMITTING TRACT (NTT) and functions in transmitting tract development in the carpel of Arabidopsis (Crawford et al, 2007).…”

“…These data indicate that increased expression of NTT was responsible for the ntt-3D mutant phenotypes, suggesting that enhanced expression of NTT affects the regulation of a variety of processes in plant development and differentiation. NTT encodes a C 2 H 2 /C 2 HC-type zinc finger protein (Englbrecht et al, 2004;Sagasser et al, 2002). The classical C 2 H 2 zinc fingers have been implicated in DNA binding, RNA binding, and protein-protein interactions and are involved in a variety of functions.…”

MtPAR MYB transcription factor acts as an on switch for proanthocyanidin biosynthesis in Medicago truncatula

“…In the nonlegume Arabidopsis, six loci are known to have regulatory functions in PA biosynthesis, TT1, TT2, TT8, TT16, TTG1, and TTG2 (6). TT1 and TT16 encode a zinc finger and a MADS box protein, respectively, and are essential for seed pigmentation (26,27). TTG2 encodes a WRKY TF, which acts downstream of TTG1 (28).…”