Abstract
A cell division-inducing factor (CDF) purified from the culture filtrates of auxin autotrophic 2B-13 cells induced semi-synchronous cell division in auxin-starved tobacco BY-2 cells. The CDF was identified as a glycoprotein, whose polypeptide chains have been found to have homology to ATP-binding cassette (ABC) transporters, while its sugar moiety has not yet been characterized. Specific binding of the CDF to several types of lectins suggests that the sugar moiety of the CDF is composed of mannose and/or galactose. Furthermore, specific binding of the CDF to β-glucosyl Yariv reagent suggests that the CDF has certain characteristics of arabinogalactan proteins. Intriguingly, the addition of increased amounts of β-glucosyl Yariv reagent to the culture medium inhibited 2,4-D induced cell division of auxin-starved BY-2 cells, suggesting that the CDF plays a pivotal role in inducing cell division in the auxin signaling pathways.
