Characterization of a pollen‐specific cDNA from sunflower encoding a zinc finger protein

Abstract

We have isolated, via differential hybridization screening of a floral cDNA library from sunflower, a cDNA clone that hybridizes to a 1100 nucleotide-long mRNA found exclusively in mature pollen grains. The cDNA encodes a 219 amino acid-long polypeptide containing two potential zinc fingers alternating with two basic domains. A similar organization is found in the erythroid-specific transcription factor Eryf1 from chicken and its murine homolog GF-1. The C-terminus of the protein contains a sixfold repeat of the pentapeptide sequence (S,T,A)(E,D)TQN. These features suggest that the SF3 protein is a transcription factor required for the expression of late pollen genes. The SF3 gene is a member of a multicopy gene family. A genomic copy of the gene has been isolated and sequenced; it is split by four short, AT-rich introns.

An Actin-Binding Protein, LlLIM1, Mediates Calcium and Hydrogen Regulation of Actin Dynamics in Pollen Tubes

“…the CRP family [Schmeichel and Beckerle, 1997;Grubinger and Gimona, 2004;Tran et al, 2005]). In flowering plants, several CRP-related LIM orthologs have been found in Arabidopsis, rice (Arnaud et al, 2007), tobacco , sunflower (Baltz et al, 1992), and lily pollen (this study). Although a few plant LIMs showed nuclear localization, such as NtWLIM1 (Thomas et al, 2006), LlLIM1 was seldom found in the vegetative nucleus of the pollen tube (data not shown).…”

“…Amino acid sequence alignment analysis (Fig. 1B) showed that LlLIM1 shared high homology with other plant LIMs having two LIM domains, such as AtWLIM1, OsWLIM1 (Arnaud et al, 2007), HaWLIM1 (Baltz et al, 1992), and NtWLIM1 . In addition, for all plant LIMs examined, the tandem zinc finger motifs present in both LIM domains contained eight conserved Cys/His residues (Fig.…”

EhLimA, a Novel LIM Protein, Localizes to the Plasma Membrane inEntamoeba histolytica

“…These protein-protein interactions are governed by a variety of protein binding domains one of which is the LIM domain. Since first described nearly 2 decades ago (21, 28, 57), LIM domain-containing proteins have been identified in a wide range of eukaryotes, including protozoa (16,30,45), plants (5,20,40), and yeast (Saccharomyces cerevisiae) (39), stressing the evolutionary importance of these proteins. In the parasitic protozoan Entamoeba histolytica, a few studies have revealed the presence of such proteins (17, 36), although to date, no LIM domain-containing proteins have been characterized in this organism.…”

EPLIN, Epithelial protein lost in neoplasm

“…Since the available polyclonal anti-EPLIN antisera do not distinguish the two known isoforms of EPLIN, we carried out in situ immunouorescence using two dierent cell lines, HOK18C (an immortalized human oral keratinocyte line), and BeWo (a human choriocarcinoma cell line). EPLIN-a is expressed as the predominant form of HOK18C, (Nagase et al, 1998), plant transcription factor SF3 (Baltz et al, 1992), and muscle LIM protein (Arber et al, 1994) is shown. The signature cysteine and histidine residues of LIM domain are indicated by bold lettering.…”