Abstract:

【Objective】 Analyzing the sequence characteristics of two wheat MBD genes, TaMBD1 and TaMBD6 and their expression patterns during the seed development and germination, which will provide an insight into epigenetic regulation mechanisms involved in the development and germination of wheat seeds. 【Method】 RACE technology was used in full-length cDNAs cloning and proper bioinformatics softwares were applied for characterizing the cloned genes and the deduced proteins. Semi-quantitative RT-PCR was performed to detect the expression patterns of cloned genes. 【Result】 Two full-length cDNAs of TaMBD1 and TaMBD6 were cloned, which encodes 193 and 187 amino acids, respectively. The amino acid sequence analysis showed that a typical methyl-CpG-binding domain was included in TaMBD1 and TaMBD6, and a CW-type Zinc finger domain was found in TaMBD1, additionally. Structure prediction revealed that both of TaMBD1 and TaMBD6 could fold into an alpha/beta sandwich structure comprising a layer of twisted beta sheet, backed by another layer formed by the alpha1 helix and loops at the C terminus. The RT-PCR analysis showed that the TaMBD1 was steadily expressed with a relative higher level during the seed development, while gradually up- and down- regulated in embryo and endosperm tissues, respectively, along with the germination of wheat seeds. The expression of TaMBD6 is vibrated during the seed development and it was highly expressed at the time point of 15 days after pollination. However, the expression of TaMBD6 was not detected during the seed germination. 【Conclusion】 Two full-length cDNAs of TaMBD1 and TaMBD6 were firstly cloned from wheat and the typical DNA binding domains were found in the deduced proteins. The expression patterns of these two genes indicated that TaMBD1 might play an importan regulating role during the seed development and germination in wheat, while TaMBD6 was only involved in the regulation of seed development. The results provided important information for further studies on molecular regulation mechanism during the seed development and germination in wheat.

Key words: methyl-binding domain protein, gene cloning, expression pattern, wheat seeds