title: Pollen-expressed transcription factor 2 encodes a novel plant-specific TFIIB-related protein that is required for pollen germination and embryogenesis in Arabidopsis.
abstract: Pollen germination and embryogenesis are important to sexual plant reproduction. The processes require a large number of genes to be expressed. Transcription of eukaryotic nuclear genes is accomplished by three conserved RNA polymerases acting in association with a set of auxiliary general transcription factors (GTFs), including B-type GTFs. The roles of B-type GTFs in plant reproduction remain poorly understood. Here we report functional characterization of a novel plant-specific TFIIB-related gene PTF2 in Arabidopsis. Mutation in PTF2 caused failure of pollen germination. Pollen-rescue revealed that the mutation also disrupted embryogenesis and resulted in seed abortion. PTF2 is expressed prolifically in developing pollen and the other tissues with active cell division and differentiation, including embryo and shoot apical meristem. The PTF2 protein shares a lower amino acid sequence similarity with other known TFIIB and TFIIB-related proteins in Arabidopsis. It can interact with TATA-box binding protein 2 (TBP2) and bind to the double-stranded DNA (dsDNA) as the other known TFIIB and TFIIB-related proteins do. In addition, PTF2 can form a homodimer and interact with the subunits of RNA polymerases (RNAPs), implying that it may be involved in the RNAPs transcription. These results suggest that PTF2 plays crucial roles in pollen germination and embryogenesis in Arabidopsis, possibly by regulating gene expression through interaction with TBP2 and the subunits of RNAPs.
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China.
authors.forename: Qian-Kun
authors.initials: QK
authors.lastname: Niu
authors.forename: Yan
authors.initials: Y
authors.lastname: Liang
authors.forename: Jing-Jing
authors.initials: JJ
authors.lastname: Zhou
authors.forename: Xiao-Ying
authors.initials: XY
authors.lastname: Dou
authors.forename: Shu-Chen
authors.initials: SC
authors.lastname: Gao
authors.forename: Li-Qun
authors.initials: LQ
authors.lastname: Chen
authors.forename: Xue-Qin
authors.initials: XQ
authors.lastname: Zhang
authors.forename: De
authors.initials: D
authors.lastname: Ye
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D002454:Cell Differentiation; D002455:Cell Division; D018744:DNA, Plant / Q000378:metabolism; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D018525:Germination; D009154:Mutation; D010641:Phenotype; D058439:Plant Somatic Embryogenesis Techniques; D011058:Pollen / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D021122:Protein Subunits / Q000378:metabolism; D013045:Species Specificity; D035581:Transcription Factor TFIIB / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D029681:Arabidopsis Proteins; D018744:DNA, Plant; C586029:PTF2 protein, Arabidopsis; D021122:Protein Subunits; D035581:Transcription Factor TFIIB; D012321:DNA-Directed RNA Polymerases
keywords: Arabidopsis.; PTF2; TFIIB-related protein; embryogenesis; pollen; transcription factor