RT Journal Article SR Electronic T1 C. elegans chromosomes connect to centrosomes by anchoring into the spindle network JF bioRxiv FD Cold Spring Harbor Laboratory SP 060855 DO 10.1101/060855 A1 Stefanie Redemann A1 Johannes Baumgart A1 Norbert Lindow A1 Sebastian Fürthauer A1 Ehssan Nazockdast A1 Andrea Kratz A1 Steffen Prohaska A1 Jan Brugués A1 Michael Shelley A1 Thomas Müller-Reichert YR 2016 UL http://biorxiv.org/content/early/2016/12/10/060855.abstract AB The mitotic spindle ensures the faithful segregation of chromosomes. To discover the nature of the crucial centrosome-to-chromosome connection during mitosis, we combined the first large-scale serial electron tomography of whole mitotic spindles in early C. elegans embryos with live-cell imaging. Using tomography, we reconstructed the positions of all microtubules in 3D, and identified their plus- and minus-ends. We classified them as kinetochore (KMTs), spindle (SMTs), or astral microtubules (AMTs) according to their positions, and quantified distinct properties of each class. While our light microscopy and mutant studies show that microtubules are nucleated from the centrosomes, we find only a few KMTs are directly connected to the centrosomes. Indeed, by quantitatively analysing several models of microtubule growth, we conclude that minus-ends of KMTs have selectively detached and depolymerized from the centrosome. In toto, our results show that the connection between centrosomes and chromosomes is mediated by an anchoring into the entire spindle network and that any direct connections through KMTs are few and likely very transient.