This short possible domain is found in a variety of plant transcription factors that contain GATA domains as well as other motifs. Although previously known as the Zim domain this is now called the tify domain after its most conserved amino acids. TIFY proteins can be further classified into two groups depending on the presence (group I) or absence (group II) of a C2C2-GATA domain. Functional annotation of these proteins is still poor, but several screens revealed a link between TIFY proteins of group II and jasmonic acid-related stress response.
The tify domain is a 36-amino acid domain only found among Embryophyta (land plants). It has been named after the most conserved amino acid pattern (TIF[F/Y]XG) it contains, but was previously known as the Zim domain. As the use of uppercase characters (TIFY) might imply that the domain is fully conserved across proteins, a lowercase lettering has been chosen in an attempt to highlight the reality of its natural variability.
Based on the domain architecture, tify domain containing proteins can be classified into two groups. Group I is formed by proteins possessing a CCT (CONSTANS, CO-like, and TOC1) domain and a GATA-type zinc finger in addition to the tify domain. Group II contains proteins characterised by the tify domain but lacking a GATA-type zinc finger. Tify domain containing proteins might be involved in developmental processes and some of them have features that are characteristic for transcription factors: a nuclear localisation and the presence of a putative DNA-binding domain [ (PUBMED:17499004) ]. Some proteins known to contain a tify domain include:
Arabidopsis thaliana GATA transcription factors (Zinc-finger protein expressed in Inflorescence Meristem, ZIM), a putative transcription factor involved in inflorescence and flower development [ (PUBMED:10945256) (PUBMED:14966217) ].
The ZIM domain was originally identified in the ZIM protein (BAA97679;Zinc-finger protein expressed in Inflorescence Meristem). Since then ithas been found in other proteins and the corresponding genes have beengrouped into a plant-specific family. However, the family lacksconsistency in its classification among different databases. Here, we tryto clarify this incongruity by presenting an overview of the Arabidopsisproteins having this domain. The presented genome-wide survey can be seenas a start point to reveal the unknown function of these proteins.Furthermore, because of the confusing ZIM nomenclature being used atpresent, we propose to rename the domain and family as tify, after themost conserved amino acid motif characterizing the members of this family.
Characterization of Arabidopsis ZIM, a member of a novel plant-specificGATA factor gene family.
J Exp Bot. 2004; 55: 631-9
Display abstract
The Arabidopsis gene ZIM encodes a putative transcription factorcontaining a novel GATA-type zinc-finger domain with a longer spacerbetween its two sets of conserved cysteine residues (C-X2-C-X20-C-X2-C).In Arabidopsis, ZIM and homologous proteins, ZML1 and ZML2, wereidentified as GATA factors containing the C-X2-C-X20-C-X2-C motif, a CCTdomain, and an uncharacterized conserved domain. Proteins that possessthis domain structure were found exclusively in plants, indicating thatthey belong to a novel family of plant-specific GATA-type transcriptionfactors. When ZIM was overexpressed using a CaMV 35S promoter inArabidopsis, hypocotyls and petioles were elongated. The elongationphenotype was observed under all wavelengths of light tested and even inthe presence of biosynthetic inhibitors of either brassinosteroid orgibberellin. In ZIM-overexpressing plants, XTH33 which is predicted tofunction in cell wall modification was detected as an up-regulated gene bymicroarray analysis, and this could account for the elongation phenotype.Genes in ZIM-overexpressing plants were identified that were up-regulatedin a tissue-specific manner, which suggests that transcriptionalregulation by ZIM and its consequent effects are spatially controlled.
Characterization of a novel gene encoding a putative single zinc-fingerprotein, ZIM, expressed during the reproductive phase in Arabidopsisthaliana.
Biosci Biotechnol Biochem. 2000; 64: 1402-9
Display abstract
By differential screening of an arrayed normalized cDNA library from theinflorescence apex in Arabidopsis, a cDNA clone having a deduced aminoacid sequence with a motif for a zinc finger was isolated as one of thegenes expressed specifically in the reproductive phase. The deducedprotein has a modular structure with a putative single C2-C2 zinc-fingermotif distantly related to a GATA-1-type finger, a basic region with asequence resembling a nuclear localization signal, and an acidic region.The gene seemed to have been formed by the exon-shuffling during itsmolecular evolution, since individual domains are encoded by discreteexons. RNA gel blot analysis showed its expression in shoot apex andflowers in the reproductive phase. The gene was named ZIM for Zinc-fingerprotein expressed in Inflorescence Meristem. The nuclear localization ofZIM was detected using GFP as a reporter. These results suggest that ZIMis a putative transcription factor involved in inflorescence and flowerdevelopment.
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