Abstract:

【Objective】 The aim of this study is to isolate and clone RBR (retinoblastoma-related) gene from barley (Hordeum vulgare), which is a negative regulator during the cell cycle progress, to characterize HvRBR sequence, ensure taxonomic status among the homologous genes, and give more information about cell proliferation and differential regulation pathway in animals and plants. 【Method】 After large numbers of RBR genes were bioinformatically analyzed, specific primers were designed based on the conservative sequences. The RBR gene sequences were obtained from both genomic DNA and cDNA of seedlings. DNAMAN software was used to perform sequence analysis, multiple sequence alignment, and phylogenetic tree construction was also carried out by MEGA. 【Result】 The 5 547 bp of DNA sequence (GU121481) and 3 179 bp of cDNA sequence (GU121480) of HvRBR were obtained from GSHO1854 (a shrunken endosperm mutational material of cultivated barley), respectively. The coding region of this gene could encode a protein with 975 amino acid residues. This deduced amino acid had a high identity with the known RBR proteins form plants and animals. Although the lower identity was found in the spacer region between pocket A and B domain, a conservative cysteine residue was found in all the RBR protein family members at similar position. It was suggested that the intra- or inter-molecular disulfide bond probably play an important role in affecting the structure and function of RBR protein. Phylogenetic analysis revealed that the highest degree of identity (84.3%) was between HvRBR and OsRBR2 (Oryza sativa), and a lower value (50%) between HvRBR and dicot plants such as MsRBR (Medicago sativa) and AtRBR1 (Arabidopsis thaliana). 【Conclusion】 It was the first time to obtain the barley HvRBR gene, which regulate cell cycle, proliferation and differentiation. HvRBR is a novel member of subgroup C of plant RBR family by sequence analysis, identification and phylogenetic analysis.

Key words: barley')">barley, RBR protein, full length coding region of cDNA, sequence analysis