KEY MESSAGE : bZIP TF network in pollen. Transcriptional control of gene expression represents an important mechanism guiding organisms through developmental processes and providing plasticity towards environmental stimuli. Because of their sessile nature, plants require effective gene regulation for rapid response to variation in environmental and developmental conditions. Transcription factors (TFs) provide such control ensuring correct gene expression in spatial and temporal manner. Our work reports the interaction network of six bZIP TFs expressed in Arabidopsis thaliana pollen and highlights the potential functional role for AtbZIP18 in pollen. AtbZIP18 was shown to interact with three other pollen-expressed bZIP TFs-AtbZIP34, AtbZIP52, and AtbZIP61 in yeast two-hybrid assays. AtbZIP18 transcripts are highly expressed in pollen, and at the subcellular level, an AtbZIP18-GFP fusion protein was located in the nucleus and cytoplasm/ER. To address the role of AtbZIP18 in the male gametophyte, we performed phenotypic analysis of a T-DNA knockout allele, which showed slightly reduced transmission through the male gametophyte. Some of the phenotype defects in atbzip18 pollen, although observed at low penetrance, were similar to those seen at higher frequency in the T-DNA knockout of the interacting partner, AtbZIP34. To gain deeper insight into the regulatory role of AtbZIP18, we analysed atbzip18/- pollen microarray data. Our results point towards a potential repressive role for AtbZIP18 and its functional redundancy with AtbZIP34 in pollen.

• MeSH
• Arabidopsis cytologie   metabolismus   ultrastruktura   MeSH
• dimerizace MeSH
• DNA rostlinná MeSH
• inzerční mutageneze MeSH
• proteiny huseníčku metabolismus   MeSH
• pyl genetika   růst a vývoj   metabolismus   ultrastruktura   MeSH
• regulace genové exprese u rostlin MeSH
• rekombinantní fúzní proteiny metabolismus   MeSH
• trans-aktivátory metabolismus   MeSH
• transkripční faktory bZIP metabolismus   MeSH
• vazba proteinů MeSH
• Publikační typ
• časopisecké články MeSH

Heat shock transcription factors (Hsfs) are involved in multiple aspects of stress response and plant growth. However, their role during male gametophyte development is largely unknown, although the generative phase is the most sensitive and critical period in the plant life cycle. Based on a wide screen of T-DNA mutant lines, we identified the atren1 mutation (restricted to nucleolus1) in early male gametophytic gene At1g77570, which has the closest homology to HSFA5 gene, the member of a heat shock transcription factor (HSF) gene family. The mutation causes multiple defects in male gametophyte development in both structure and function. Because the mutation disrupts an early acting (AtREN1) gene, these pollen phenotype abnormalities appear from bicellular pollen stage to pollen maturation. Moreover, the consequent progamic phase is compromised as well as documented by pollen germination defects and limited transmission via male gametophyte. In addition, atren1/- plants are defective in heat stress (HS) response and produce notably higher proportion of aberrant pollen grains. AtREN1 protein is targeted specifically to the nucleolus that, together with the increased size of the nucleolus in atren1 pollen, suggests that it is likely to be involved in ribosomal RNA biogenesis or other nucleolar functions.

• MeSH
• alely MeSH
• Arabidopsis cytologie   růst a vývoj   metabolismus   MeSH
• buněčné jadérko metabolismus   MeSH
• DNA bakterií genetika   MeSH
• DNA vazebné proteiny genetika   metabolismus   MeSH
• exony genetika   MeSH
• fenotyp MeSH
• klíčení MeSH
• mutace genetika   MeSH
• penetrance MeSH
• proteiny huseníčku genetika   metabolismus   MeSH
• pyl cytologie   genetika   růst a vývoj   MeSH
• pylová láčka cytologie   genetika   růst a vývoj   MeSH
• reakce na tepelný šok * genetika   MeSH
• regulace genové exprese u rostlin MeSH
• segregace chromozomů genetika   MeSH
• testy genetické komplementace MeSH
• transport proteinů MeSH
• vývojová regulace genové exprese MeSH
• zelené fluorescenční proteiny metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH