BP

GO:0007020

microtubule nucleation

The process in which tubulin alpha-beta heterodimers begin aggregation to form an oligomeric tubulin structure (a microtubule seed). Microtubule nucleation is the initiating step in the formation of a microtubule in the absence of any existing microtubules ('de novo' microtubule formation).

NAS

BP

GO:0007126

meiotic nuclear division

One of the two nuclear divisions that occur as part of the meiotic cell cycle.

IBA

BP

GO:0007338

single fertilization

The union of male and female gametes to form a zygote.

NAS

BP

GO:0031122

cytoplasmic microtubule organization

A process that is carried out at the cellular level which results in the assembly, arrangement of constituent parts, or disassembly of structures formed of microtubules and associated proteins in the cytoplasm of a cell.

IBA

BP

GO:0051298

centrosome duplication

The replication of a centrosome, a structure comprised of a pair of centrioles and peri-centriolar material from which a microtubule spindle apparatus is organized.

IBA

BP

GO:0051415

interphase microtubule nucleation by interphase microtubule organizing center

The 'de novo' formation of a microtubule by the interphase microtubule organizing center during interphase, the stage of cell cycle between successive rounds of chromosome segregation.

IBA

BP

GO:0090307

mitotic spindle assembly

The aggregation, arrangement and bonding together of a set of components to form the spindle that contributes to the process of mitosis.

IBA

CC

GO:0000923

equatorial microtubule organizing center

A microtubule organizing center formed by a band of gamma-tubulin that is recruited to a circumferential band of F-actin at the midpoint of a cell and which nucleates microtubules from the cell division site at the end of mitosis.

IBA

CC

GO:0005737

cytoplasm

All of the contents of a cell excluding the plasma membrane and nucleus, but including other subcellular structures.

IDA

CC

GO:0005813

centrosome

A structure comprised of a core structure (in most organisms, a pair of centrioles) and peripheral material from which a microtubule-based structure, such as a spindle apparatus, is organized. Centrosomes occur close to the nucleus during interphase in many eukaryotic cells, though in animal cells it changes continually during the cell-division cycle.

IDA|NAS

CC

GO:0005814

centriole

A cellular organelle, found close to the nucleus in many eukaryotic cells, consisting of a small cylinder with microtubular walls, 300-500 nm long and 150-250 nm in diameter. It contains nine short, parallel, peripheral microtubular fibrils, each fibril consisting of one complete microtubule fused to two incomplete microtubules. Cells usually have two centrioles, lying at right angles to each other. At division, each pair of centrioles generates another pair and the twin pairs form the pole of the mitotic spindle.

IDA

CC

GO:0005819

spindle

The array of microtubules and associated molecules that forms between opposite poles of a eukaryotic cell during mitosis or meiosis and serves to move the duplicated chromosomes apart.

NAS

CC

GO:0005827

polar microtubule

Any of the spindle microtubules that come from each pole and overlap at the spindle midzone. This interdigitating structure consisting of antiparallel microtubules is responsible for pushing the poles of the spindle apart.

IDA

CC

GO:0005829

cytosol

The part of the cytoplasm that does not contain organelles but which does contain other particulate matter, such as protein complexes.

TAS

CC

GO:0008275

gamma-tubulin small complex

A complex usually comprising two gamma-tubulin molecules and two conserved non-tubulin proteins. Some gamma-tubulin small complexes are thought to be the repeating unit making up the core of the gamma-tubulin ring complex.

IBA

CC

GO:0016020

membrane

A lipid bilayer along with all the proteins and protein complexes embedded in it an attached to it.

IDA

MF

GO:0005198

structural molecule activity

The action of a molecule that contributes to the structural integrity of a complex or assembly within or outside a cell.

NAS

MF

GO:0005200

structural constituent of cytoskeleton

The action of a molecule that contributes to the structural integrity of a cytoskeletal structure.

IBA|NAS

MF

GO:0005515

protein binding

Interacting selectively and non-covalently with any protein or protein complex (a complex of two or more proteins that may include other nonprotein molecules).

IPI

MF

GO:0043015

gamma-tubulin binding

Interacting selectively and non-covalently with the microtubule constituent protein gamma-tubulin.

IDA

MF

GO:0051011

microtubule minus-end binding

Interacting selectively and non-covalently with the minus end of a microtubule.

IBA