engleski

Functional analysis of MATH/BTB domain proteins specifically expressed in egg cells and at the onset of embryogenesis.

The conserved BTB and MATH domains are presented in a variety of proteins as a single copy domain, together or in combination with other types of domains. Different functional roles have been identified for BTB proteins such as transcription repression, cytoskeleton regulation as well as protein ubiquitination/degradation in which amino-terminal MATH domain is responsible for substrate specificity. Althoug the function of MATH/BTB proteins is not clear, distribution of these proteins from yeast to human and domain conservation suggest that they are critical in some cellular functions. By screening cDNA libraries of isolated unfertilized egg cells and two-celled proembryos of wheat we have identified several ESTs (expressed sequence tags) which represent completely novel transcripts. Among these, two transcripts encoding proteins with MATH/BTB domains 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 and 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.

MATH-BTB; embryogenesis; wheat

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