Molecular cloning and expression analysis of a RanBP2 zinc finger protein gene in upland cotton (Gossypium hirsutum L.).

Gossypol is an important resistant substance of Gossypium, and its storage organ is pigment gland. Although, the relationship between gossypol and pigment gland has been studied for a long time, the development mechanism of pigment gland has not been revealed up to now in molecular perspective. On the basis of differentially expressed cDNAs fragments at the stage of the cotton gland development using suppression subtractive hybridization (SSH), the complete cDNA sequence of a novel RanBP2 zinc finger protein (ZFP) gene was cloned by rapid amplification of cDNA ends (RACE) from upland cotton (Gossypium hirsutum L.), Xiangmian 18. The cotton RanBP2 ZFP cDNA (GenBank accession number: DQ173926) is 717 base pair (bp) long with an open reading frame encoding 139 amino acids, which encodes a 15.6 kDa protein. The cotton RanBP2 ZFP had three Ran-binding protein (RanBP) two zinc finger motifs and belonged to RanBP2 ZFP family. There is a 292-base non-coding sequence at 3' cDNA end, which includes polyA sequence. Sequence alignment analysis revealed that the cDNA nucleotide and its deduced amino acid sequence are moderately identical to the putative ZFP from other species. The mRNA expressing profiles of the novel ZFP gene was investigated by reverse transcription-polymerase chain reaction (RT-PCR). The result showed that it expressed at different development stages of gland, including the undeveloped stage, developing stage, developed stage and cotyledon stage. However, with the development of pigment gland, the mRNA levels in the gland-developed seed and cotyledon were increased to about 1.5 and 2 folds of that in gland-undeveloped seed, respectively, which suggested that the novel ZFP played a role in the development of the cotton gland.