Figure 10: Ubiquitination analysis and a summary of PTB1 function.
From: Natural variation in PTB1 regulates rice seed setting rate by controlling pollen tube growth
(a) Ubiquitination analysis of PTB1 (GST-RING). BnTR1 and PTB1 (GST-RING) fusion proteins were assayed for E3 activity in the presence of E1, E2 and ubiquitin. (b) A sketch illustrating that the expression level of PTB1 positively regulates PT growth in rice reproductive tract. PTB1 function loss caused early arrests of PT growth, and a lower expression level caused late arrests. A moderate expression level also led to late arrests, although some PTs reached the micropyle. However, a higher expression level generated several normally growing PTs that resulted in fertilization. (c) A proposed model for the role of PTB1 in the regulation of rice PSSR and yield. The steps within the box marked using a black dotted line are currently unknown.
