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.

Gene expression atlas of pigeonpea and its application to gain insights into genes associated with pollen fertility implicated in seed formation

“…C.cajan_07765 , annotated as SF3 protein, displayed a high and specific expression in floral tissues including bud, flower, pistil, stamen, petal, and sepal. This gene has been previously reported as a TF regulating the expression of late pollen genes (Baltz et al , 1992 a ) and has been found to be connected to 13 other genes in the co-expression network (Fig. 7C).…”

“…The brown module revealed pigeonpea genes involved in late pollen maturation, pollen tube formation and fertilization. The ‘hub’ gene of the network ( C.cajan_07765 ) was a pollen-specific SF3 gene, which is a developmentally regulated TF, well documented in Arabidopsis to play a role in expression of late pollen genes, pollen tube formation and fertilization events (Baltz et al , 1992a, b). Another ‘hub’ gene, C.cajan_35396 codes for a H + -symporting sucrose transporter protein 2, typically named SUC2 protein, responsible for loading sucrose into sink cells such as developing pollen (Sauer, 2007) and other floral tissues.…”

Genome-Wide Analysis of LIM Gene Family in Populus trichocarpa, Arabidopsis thaliana, and Oryza sativa

“…The distribution of 10 062 poplar ESTs in different wood cDNA libraries 16 revealed that a cDNA, named PtaGLIM1a (EF035035), homologous to the LIM protein SF3 8 was abundant in differentiating xylem from tension wood. Five other PtaLIM cDNAs present in this EST collection were found, and a complete sequence was determined for each.…”

“…Later renamed HaPLIM1 , SF3 expression was found specific to sunflower pollen. 8,9 The LIM proteins from sunflower, tobacco, and Arabidopsis have been classified into four groups: PLIM1 and PLIM2 specifically expressed in pollen and WLIM1 and WLIM2 expressed in the whole plant. 7 Like animal CRP, most plant LIM proteins are present in the cytoplasm and/or in the nucleus.…”

De novo Sequencing and Comparative Transcriptomics of Floral Development of the Distylous Species Lithospermum multiflorum

“…Later in development, DE genes and GO terms have been demonstrated to be involved in pollen-specific responses, reproduction, and cell signaling, all of which may play a role in SI. During this stage of development, DE genes include pollen allergen ole e 6-like protein, ole e 1-like protein, pollen-specific protein sf3-like, and protein-tyrosine kinase 2-beta-like (Table 3), while overrepresented CC GO terms comprise extracellular region, cell wall, plasma membrane (Table 6) (Baltz et al, 1992a,b; Hubbard and Till, 2000; Staiger and Franklin-Tong, 2003; Jiménez-López et al, 2011; Lopez-Casado et al, 2012). This pattern of expression demonstrates a shift in the function of DE genes between early and late development.…”