title: Specific association of transcripts of tbzF and tbz17, tobacco genes encoding basic region leucine zipper-type transcriptional activators, with guard cells of senescing leaves and/or flowers.
abstract: Induction by low temperature is a common feature of the lip19 subfamily members of the basic region leucine zipper gene family in plants. Here, we characterize two tobacco (Nicotiana tabacum) genes, tbzF and tbz17, belonging to the lip19 subfamily, whose gene products, TBZF and TBZ17, show 73% identity and are located in nuclei. They preferentially bind to DNA fragments spanning A-box/G-box and C-box/G-box hybrid motifs and show transactivation activity in cobombarded tobacco BY-2 cells, indicating they function as transcriptional activators. Transcripts of tbzF were detected at a high level in senescing leaves and flowers. In contrast, tbz17 transcripts could be shown to accumulate in aged leaves but not in flowers. In situ hybridization analysis revealed transcripts of tbzF and tbz17 to be predominantly located in guard cells and vascular tissues of senescing leaves. These results suggest that TBZF and TBZ17 are both involved in controlling gene transcription related to functions of guard cells in senescing leaves and that TBZF bifunctionally acts in floral development.
authors.affiliation: Research and Education Center for Genetic Information, Nara Institute of Science and Technology, Ikoma, Nara 630-0101, Japan.
authors.forename: S H
authors.initials: SH
authors.lastname: Yang
authors.forename: T
authors.initials: T
authors.lastname: Berberich
authors.forename: H
authors.initials: H
authors.lastname: Sano
authors.forename: T
authors.initials: T
authors.lastname: Kusano
mesh_terms: D000595:Amino Acid Sequence; D050976:Basic-Leucine Zipper Transcription Factors; D002467:Cell Nucleus / Q000378:metabolism; D016922:Cellular Senescence; D002734:Chlorophyll / Q000032:analysis; D004268:DNA-Binding Proteins / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D016350:Leucine Zippers / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D010940:Plant Proteins / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D018514:Plant Structures / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D016415:Sequence Alignment; D014026:Nicotiana / Q000235:genetics* / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics* / Q000378:metabolism; D015533:Transcriptional Activation
chemical_list: D050976:Basic-Leucine Zipper Transcription Factors; D004268:DNA-Binding Proteins; C082457:Lip19 protein, Oryza sativa; D010940:Plant Proteins; C438370:TBZF protein, Nicotiana tabacum; D015534:Trans-Activators; D002734:Chlorophyll