[Identification and expression analysis of a full-length cDNA encoding Brassica napus small nuclear ribonucleoprotein BnSmD1].

By using substractive hybridization (SSH) and rapid amplification of cDNA ends-polymerase chain reaction (RACE-PCR), a full-length cDNA encoding Brassica napus small nuclear ribonucleoprotein, named BnSmD1, was obtained. It had 484 base pairs in length containing an open reading frame (ORF) of 354 bp and encoding a predicted protein of 118 amino acids with a molecular weight of 13 kDa. The BnSmD1 protein shares two highly conserved Sm folds (Sm-1 and Sm-2) and a C-terminal RG dipeptide repeat. Northern blot analysis revealed that BnSmD1 was expressed in all tested organs in B. napus, but its transcript level in early floral buds was much higher than that in leaf and stem tissues. No obvious expression difference was observed in leaf and stem tissues between the apetalous line Apet33-10 petalled near-isogenic line Pet33-10. Compared with wild type, the expression of BnSmD1 in the early floral buds of apetalous mutant Apet33-10 was significantly reduced. Taken together, our results suggest that BnSmD1 may play an important role in early floral petal development in B. napus.