Verelst Wim, Twell David, de Folter Stefan, Immink Richard, Saedler Heinz, Münster Thomas
Department of Molecular Plant Genetics, Max-Planck-Institute for Plant Breeding Research, Carl-von-Linné-Weg, 50829 Cologne, Germany.
Genome Biol. 2007;8(11):R249. doi: 10.1186/gb-2007-8-11-r249.
Differentiation processes are responsible for the diversity and functional specialization of the cell types that compose an organism. The outcome of these processes can be studied at molecular, physiologic, and biochemical levels by comparing different cell types, but the complexity and dynamics of the regulatory processes that specify the differentiation are largely unexplored.
Here we identified the pollen-specific MIKC* class of MADS-domain transcription factors as major regulators of transcriptome dynamics during male reproductive cell development in Arabidopsis thaliana. Pollen transcript profiling of mutants deficient in different MIKC* protein complexes revealed that they control a transcriptional switch that directs pollen maturation and that is essential for pollen competitive ability. We resolved the functional redundancy among the MIKC* proteins and uncovered part of the underlying network by identifying the non-MIKC* MADS-box genes AGL18 and AGL29 as downstream regulators of a subset of the MIKC* MADS-controlled genes.
Our results provide a first, unique, and compelling insight into the complexity of a transcription factor network that directs cellular differentiation during pollen maturation, a process that is essential for male reproductive fitness in flowering plants.
分化过程决定了构成生物体的细胞类型的多样性和功能特化。通过比较不同的细胞类型，可以在分子、生理和生化水平上研究这些过程的结果，但是决定分化的调控过程的复杂性和动态性在很大程度上尚未被探索。
在这里，我们鉴定出花粉特异性的MIKC类MADS结构域转录因子是拟南芥雄性生殖细胞发育过程中转录组动态变化的主要调节因子。对不同MIKC蛋白复合体缺陷型突变体的花粉转录谱分析表明，它们控制着一个指导花粉成熟的转录开关，而这对花粉竞争能力至关重要。我们解析了MIKC蛋白之间的功能冗余，并通过鉴定非MIKC MADS盒基因AGL18和AGL29作为MIKC* MADS控制的一部分基因的下游调节因子，揭示了部分潜在网络。
我们的结果首次对一个转录因子网络的复杂性提供了独特且有说服力的见解，该网络在花粉成熟过程中指导细胞分化，这一过程对开花植物的雄性生殖适应性至关重要。
