GATA transcription factors are widespread eukaryotic regulators whose DNA-binding domain is a class IV zinc finger motif in the form CX(2)CX(17-20)CX(2)C followed by a basic region. In fungi, they act as transcriptional activators or repressors in several different processes, ranging from nitrogen source utilization to mating-type switching. Using an in-house bioinformatics portal system, we surveyed 50 fungal and 9 out-group genomes and identified 396 putative fungal GATA transcription factors. The proportion of GATA transcription factors within a genome varied among taxonomic lineages. Subsequent analyses of phylogenetic relationships among the fungal GATA transcription factors, as well as a study of their domain architecture and gene structure, demonstrated high degrees of conservation in type IVa and type IVb zinc finger motifs and the existence of distinctive clusters at least at the level of subphylum. The SFH1 subgroup with a 20-residue loop was newly identified, in addition to six well-defined subgroups in the subphylum Pezizomycotina. Furthermore, a novel GATA motif with a 21-residue loop (CX(2)CX(21)CX(2)C, designated 'zinc finger type IVc') was discovered within the phylum Basidiomycota. Our results suggest that fungal GATA factors might have undergone multiple distinct modes of evolution resulting in diversified cellular modulation in fungi.
Basidiomycota ; Computational Biology ; Fingers ; Fungi* ; GATA Transcription Factors* ; Genome ; Nitrogen ; Portal System ; Zinc Fingers

OBJECTIVETo investigate the effects of panax notoginseng saponins (PNS) on expression, regulation and phosphorylation of multiple protein kinases in mitogen activated protein kinase (MAPK) intracellular signal pathway and GATA transcription factors in hematopoietic cells, so as to explore its mechanism of proliferation and differentiation activity on hematopoiesis.

METHODSThe human granulocytic HL-60, erythrocytic K562, megakaryocytic CHRF-288 and Meg-01 cell lines were treated by PNS, the positive control of K562, CHRF-288 cells treated by recombination human erythropoietin (Epo) and thrombopoietin (Tpo) respectively. The total cell lysate and nuclei protein were extracted after being treated by PNS, subsequently, analyzed by both Western blot and immune-precipitation. Meanwhile, the nuclei extract was performed for electrophoretic mobility shift assay (EMSA) by using (32)P radio labeled double-stranded GATA consensus oligonucleotide.

RESULTSThe expression levels of kinase MEK-1, MEK-2, ERK-1, ERK-2, AKT-1, AKT-2 and PI-3K were increased by PNS treatment to different extent in four cell lines, depending on cellular heterogeneity and sensitivity to PNS, also phosphorylation of MEK-1, ERK-1 was differentially promoted by PNS respectively P<0.05, 0.01, 0.001). The expression levels of transcription factors GATA-1 and GATA-2 were increased, moreover, their DNA binding activities were raised dramatically in PNS treated K562, CHRF-288 and Meg-01 cells compared with the controls respectively (P<0.05, 0.01, 0.001). The positive control of K562, CHRF-288 cells treated by Epo or Tpo respectively also displayed up-regulation of protein kinases and GATA transcription factors respectively (P<0.05, 0.01, 0.001).

CONCLUSIONThe results indicated that intracellular signal pathway initiated by PNS was involved in MAPK pathway and transcription factors of GATA family in hematopoietic cells. PNS displayed the role to promote proliferation and differentiation, by means of increasing expression level and phosphorylation status of multiple protein kinases, also inducing synthesis of GATA transcription factors and upregulation its DNA binding activity.

Blotting, Western ; Cell Line, Tumor ; DNA ; metabolism ; Electrophoretic Mobility Shift Assay ; Extracellular Signal-Regulated MAP Kinases ; metabolism ; GATA Transcription Factors ; metabolism ; Hematopoietic Stem Cells ; drug effects ; enzymology ; Humans ; Immunoprecipitation ; Mitogen-Activated Protein Kinase Kinases ; metabolism ; Panax notoginseng ; chemistry ; Phosphatidylinositol 3-Kinases ; metabolism ; Phosphorylation ; drug effects ; Protein Binding ; drug effects ; Protein Kinases ; metabolism ; Proto-Oncogene Proteins c-akt ; metabolism ; Saponins ; pharmacology ; Up-Regulation ; drug effects