Identification of a Ribose-Phosphate Pyrophosphokinase that Can Interact In Vivo with the Anaphase Promoting Complex/Cyclosome.

5-Phospho-d-ribosyl-1-diphosphate (PRPP) synthase (PRS) catalyzes the biosynthesis of PRPP, which is an important compound of metabolism in most organisms. However, no genes have been cloned, let alone studied for their biological function in rubber tree. In this study, we identify a novel protein (PRS4) that interacts in vivo with rubber tree anaphase promoting complex/cyclosome (APC/C) subunit 10 (HbAPC10) by yeast two-hybrid assays. has been cloned from rubber tree and named as . Blastp search in the genome of showed that HbPRS4 shared the highest similarity with AtPRS4, with 80.71% identity. qRT-PCR was used to determine the expression of in different tissues and under various treatments. was preferentially expressed in the bark. Moreover, the expression level of was significantly induced by the proteasome inhibitor MG132 treatment, suggesting it might be regulated by the ubiquitin/26S proteasome pathway. The amount of transcript was obviously decreased after mechanical wounding and abscisic acid (ABA) treatments, while a slight increase was observed at 24 h after ABA treatment. transcript in the latex was significantly upregulated by ethephon (ET) and methyl jasmonate (MeJA) treatments. These results suggested that HbPRS4 may be a specific substrate of HbAPC10 indirectly regulating natural rubber biosynthesis in rubber tree.