This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Faithful chromosome segregation during meiosis and mitosis depends on assembly of the microtubules (MTs) into a bipolar spindle. The meiotic spindle of the C. elegans ovum is morphologically distinct from the first mitotic spindle of the zygote, yet both structures form in the same cytoplasm approximately 20 minutes apart. Instead of nucleating from centrosomes as in mitosis, meiotic MTs polymerize initially around chromatin. Chromatin-associated plus-end directed motor proteins have been implicated in pushing MT minus ends away from the chromatin, and the MT array is then focused into two opposing poles. Recently the mei-1 and mei-2 genes of C. elegans were found to be required for meiotic spindle formation but not for mitotic spindle function. Genetic analysis has shown that mei-1 and mei-2 genes are the katanin orthologues in C. elegans. Katanin is a heterodimeric MT-severing protein consisting of a catalytic and a regulatory subunit. Loss-of-function mutations result in disorganized meiotic spindles and meiotic failure, but the subsequent mitotic spindles are normal. In contrast, gain-of-function mutations result in normal meiosis followed by mitosis on short spindles. These observations suggest that the MT severing activity of katanin may explain how meiotic spindles maintain their small size in a cytoplasm environment that later supports the assembly of a much larger mitotic spindle. We have produced serial tomograms from two female meiotic spindles and found that the majority (~80%) of the pole-proximal MT ends are open, in contrast to the closed/capped ends that predominate at the centrosome of the mitotic spindle. We are currently preparing strains with gain and loss-of-function mutations in mei-1 to determine how the 3D arrangements and morphology of MTs are affected by the function of katanin-like proteins during meiosis.
| Giddings Jr, Thomas H; Morphew, Mary K; McIntosh, J Richard (2017) Preparing Fission Yeast for Electron Microscopy. Cold Spring Harb Protoc 2017: |
| Zhao, Xiaowei; Schwartz, Cindi L; Pierson, Jason et al. (2017) Three-Dimensional Structure of the Ultraoligotrophic Marine Bacterium ""Candidatus Pelagibacter ubique"". Appl Environ Microbiol 83: |
| Brown, Joanna R; Schwartz, Cindi L; Heumann, John M et al. (2016) A detailed look at the cytoskeletal architecture of the Giardia lamblia ventral disc. J Struct Biol 194:38-48 |
| Saheki, Yasunori; Bian, Xin; Schauder, Curtis M et al. (2016) Control of plasma membrane lipid homeostasis by the extended synaptotagmins. Nat Cell Biol 18:504-15 |
| Höög, Johanna L; Lacomble, Sylvain; Bouchet-Marquis, Cedric et al. (2016) 3D Architecture of the Trypanosoma brucei Flagella Connector, a Mobile Transmembrane Junction. PLoS Negl Trop Dis 10:e0004312 |
| Park, J Genevieve; Palmer, Amy E (2015) Properties and use of genetically encoded FRET sensors for cytosolic and organellar Ca2+ measurements. Cold Spring Harb Protoc 2015:pdb.top066043 |
| McCoy, Kelsey M; Tubman, Emily S; Claas, Allison et al. (2015) Physical limits on kinesin-5-mediated chromosome congression in the smallest mitotic spindles. Mol Biol Cell 26:3999-4014 |
| Höög, Johanna L; Lötvall, Jan (2015) Diversity of extracellular vesicles in human ejaculates revealed by cryo-electron microscopy. J Extracell Vesicles 4:28680 |
| Marc, Robert E; Anderson, James R; Jones, Bryan W et al. (2014) The AII amacrine cell connectome: a dense network hub. Front Neural Circuits 8:104 |
| Weber, Britta; Tranfield, Erin M; Höög, Johanna L et al. (2014) Automated stitching of microtubule centerlines across serial electron tomograms. PLoS One 9:e113222 |
Showing the most recent 10 out of 84 publications
