辣椒水通道蛋白基因CaAQP的克隆与序列分析

he aquaporins (AQPs) are a family of small integral membrane proteins that facilitate water transport across biological membranes. The gene encoding the Capsicum annuum L aquaporin cDNA (designated as CaAQP, GenBank Accessin No. GU116569) was cloned from leaf of Capsicum annuum cv. P70 under 4℃ stress by cDNA-AFLP and RACE (rapid-amplification of cDNA ends). The CaAQP cDNA was 1032 bp in length, which included a potential open reading frame of 753 bp, a 5'-untranslated region (5'-UTR) of 69 bp and a 3'-untranslated region (3'-UTR) of 210 bp, encoded a protein of 250 amino acids with a predicted molecular mass of 25.7KD. Bioinformatics analyze showed that CaAQP exhibited a typical structure with six membrane-spanning domains and an internal symmetry showing two highly conserved Asn-Pro-Ala (NPA) motifs, and possessing the MIP family signal consensus sequence. The CaAQP amino acids showed high identity to other 10 plant species TIP subfamily by NCBI homology comparison analysis. Phylogenetic analysis indicated that CaAQP was clustered with the SLAQP from Solanum lycopersicum. Semi-quantitative RT-PCR analysis showed that the expression of CaAQP was down-regulated by low temperature stress.