Abstract
Mammalian epithelial cells use a pair of parental centrioles and numerous deuterosomes as platforms for efficient basal body production during multiciliogenesis. How deuterosomes form and function, however, remain controversial. They are proposed to arise either spontaneously for massive de novo centriole biogenesis or in a daughter centriole-dependent manner as shuttles to carry away procentrioles assembled at the centriole. Here, we show that both parental centrioles are dispensable for deuterosome formation. In both mouse tracheal epithelial and ependymal cells (mTECs and mEPCs), discrete deuterosomes in the cytoplasm are initially procentriole-free. They emerge at widely dispersed positions in the cytoplasm and then enlarge, concomitant with their increased ability to form procentrioles. More importantly, deuterosomes still form efficiently in mEPCs whose daughter centriole or even both parental centrioles are eliminated through shRNA-mediated depletion or drug inhibition of Plk4, a kinase essential to centriole biogenesis in both cycling cells and multiciliated cells. Therefore, deuterosomes can be assembled autonomously to mediate de novo centriole amplification in multiciliated cells.