engleski

MATH/BTB domain proteins and their role during egg cell maturation and early embryogenesis of wheat

Plant embryogenesis is a unique process in which the fertilized egg cell as a single totipotent cell cleaves many times to give rise to a functional multicellular organism. Compared to animals, little is known about the transcript composition stored in plant egg cells and the genes expressed very early after fertilization. We have used isolated unfertilized egg cells and two-celled proembryos of wheat to generate cDNA libraries and to analyze their transcripts (Sprunck et al., 2005, Plant J.). With this approach, we have identified several ESTs (expressed sequence tags) of the egg cell and the 2-celled proembryo, which represent completely novel transcripts not represented in public data bases. Among these, two transcripts encoding proteins with MATH/BTB domains (MATH-meprin and tumor necrosis factor receptor-associated factors homology domain, BTB– also known as POZ domain) have been identified in egg cells (TaMATH/BTB-Ec) and 2-celled proembryos (TaMATH/BTB-2c), respectively. A third transcript encoding a MATH/BTB protein (TaMATH/BTB) revealed similarity to published ESTs. Expression of the MATH/BTB genes was analyzed in different vegetative tissues, egg cells and zygotes as well as during embryo development. TaMATH/BTB was found to be expressed ubiquitously, while transcript of TaMATH/BTB-Ec is only present in the egg cell. TaMATH/BTB-2c is induced after fertilization, with the highest expression level in 2-celled stage proembryo. Subcellular localization of TaMATH/BTB-2c was analyzed after generating GFP-fusion proteins. Besides the complete coding region, deletions of either MATH or BTB domain were fused to GFP. Expression and subcellular localization indicates a putative role of TaMATH/BTB-2c in cell polarity. Current work includes the down-regulation of TaMATH/BTB-2c using RNAi and the identification of interaction partners.

MATH/BTB; egg cell; zygote; wheat

nije evidentirano