Coordination of PsAS1 and PsASPG expression controls timing of re-allocated N utilization in hypocotyls of pine seedlings.

摘要: During pine seed germination, a large amount of N mobilized from the storage proteins is re-allocated in hypocotyl as free asparagine, result high levels asparagine synthetase (AS) encoded by PsAS1 gene. To determine role this reserve, full-length cDNA encoding l-asparaginase (ASPG) has been cloned Scots (Pinus sylvestris L.) seedlings and characterized. Like other N-terminal nucleophile hydrolases, ASPG requires post-translational processing to exhibit enzymatic activity. However, contrast previous reports on plant ASPGs, purified recombinant does not undergo autoproteolytic cleavage vitro. Our results suggest that accessory assist proteolysis or proper folding before autocleavage divalent cation-dependent manner. Sequence comparison analysis revealed protein included K+-dependent subfamily ASPGs. The expression ASPG-encoding gene (PsASPG) was higher organs with extensive secondary development vascular system. increase transcript abundance observed at advanced stages concomitant decrease remarkable number xylem elements highly lignified cell walls. These results, together precise localization PsASPG transcripts cells cambial region, temporally coordinated, control re-allocation toward be later used during early