The phase of mitosis during which sister chromatids separate and move to opposite poles of the spindle.
anaphase-promoting complex/cyclosome (APC/C)
A ubiquitin ligase that triggers progression from metaphase to anaphase by signaling the degradation of cyclin B and cohesins.
ATM
A protein kinase that recognizes damaged DNA and leads to cell cycle arrest.
ATR
A protein kinase related to ATM that leads to cell cycle arrest in response to DNA damage.
Aurora kinase
A protein kinase family involved in mitotic spindle formation, kinetochore function, and cytokinesis.
Cdk
A member of a family of cyclin dependent protein kinases that control the cell cycle of eukaryotes.
Cdk inhibitor (CKI)
Member of a family of proteins that bind Cdk’s and inhibit their activity.
Cdk1
A protein-serine/threonine kinase that is a key regulator of mitosis in eukaryotic cells.
cell cycle checkpoint
A regulatory point that prevents entry into the next phase of the cell cycle until the events of the preceding phase have been completed.
centromere
A specialized chromosomal region that connects sister chromatids and attaches them to the mitotic spindle.
centrosome
The microtubule-organizing center in animal cells.
checkpoint kinase (CHK1 and CHK2)
A protein kinase that brings about cell cycle arrest in response to damaged DNA.
chiasma
Site of recombination that links homologous chromosomes during meiosis.
cohesin
A protein that maintains the connection between sister chromatids.
condensin
A protein complex that drives metaphase chromosome condensation.
contractile ring
A structure of actin and myosin II that forms beneath the plasma membrane during mitosis and mediates cytokinesis.
cytokinesis
Division of a cell following mitosis or meiosis.
cytostatic factor (CSF)
A cytoplasmic factor that arrests oocyte meiosis at metaphase II.
diakinesis
The final stage of the prophase of meiosis I during which the chromosomes fully condense and the cell progresses to metaphase.
diplotene
The stage of mieosis I during which homologous chromosomes separate along their length but remain associated at chiasmata.
DNA damage checkpoint
A cell cycle checkpoint that ensures that damaged DNA is not replicated and passed on to daughter cells.
E2F
A family of transcription factors that regulate the expression of genes involved in cell cycle progression and DNA replication.
fertilization
The union of a sperm and an egg.
flow cytometer
An instrument that measures the fluoresence intensity of individual cells.
fluorescence-activated cell sorter
An instrument that sorts individual cells on the basis of their fluorescence intensity.
G0
A quiescent state in which cells remain metabolically active but do not proliferate.
G1 cyclin (Cln)
A yeast cyclin that controls passage through START.
G1 phase
The phase of the cell cycle between the end of mitosis and the begining of DNA synthesis.
G2 phase
The phase of the cell cycle between the end of S phase and the begining of mitosis.
interphase
The period of the cell cycle between mitoses that includes G1, S, and G2 phases.
kinetochore
A specialized structure consisting of proteins attached to a centromere that mediates the attachment and movement of chromosomes along the mitotic spindle.
leptotene
The initial stage of the extended prophase of meiosis I during which homologous chromosomes pair before condensation.
M phase
The mitotic phase of the cell cycle.
maturation promoting factor (MPF)
A complex of Cdk1 and cyclin B that promotes entry into the M phase of either mitosis or meiosis.
meiosis
The division of diploid cells to haploid progeny, consisting of two sequential rounds of nuclear and cellular division.
metaphase
The phase of mitosis during which the chromosomes are aligned on a metaphase plate in the center of the cell.
mitosis
Nuclear division.
mitotic spindle
An array of microtubules extending from the spindle poles that is responsible for separating daughter chromosomes during mitosis. See also kinetochore microtubules, polar microtubules, chromosomal microtubules, and astral microtubules.
Mos
A protein kinase that is required for progression from meiosis I to meiosis II and maintenance of metaphase II arrest in vertebrate oocytes.
p53
A transcription factor (encoded by the p53 tumor suppressor gene) that arrests the cell cycle in G1 in response to damaged DNA and is required for apoptosis induced by a variety of stimuli.
pachytene
The stage of meiosis I during which recombination takes place between homologous chromosomes.
polar body
A small cell formed by asymmetric cell division following meiosis of oocytes.
Polo-like kinase
A protein kinase involved in mitotic spindle formation, kinetochore function, and cytokinesis.
prometaphase
A transition period between prophase and metaphase during which the microtubules of the mitotic spindle attach to the kinetochores and the chromosomes shuffle until they align in the center of the cell.
pronucleus
One of the two haploid nuclei in a newly fertilized egg.
prophase
The beginning phase of mitosis, marked by the appearance of condensed chromosomes and the development of the mitotic spindle.
Rb
A transcriptional regulatory protein that controls cell cycle progression and is encoded by a tumor suppressor gene that was identified by the genetic analysis of retinoblastoma.
restriction point
A regulatory point in animal cell cycles that occurs late in G1. After this point, a cell is committed to entering S and undergoing one cell division cycle.
S phase
The phase of the cell cycle during which DNA replication occurs.
spindle assembly checkpoint
A cell cycle checkpoint that monitors the alignment of chromosomes on the metaphase spindle.
START
A regulatory point in the yeast cell cycle that occurs late in G1. After this point a cell is committed to entering S and undergoing one cell division cycle.
synapsis
The association of homologous chromosomes during meiosis.
synaptomenal complex
A zipperlike protein structure that forms along the length of paired homologous chromosomes during meiosis.
telophase
The final phase of mitosis, during which the nuclei re-form and chromosomes decondense.
tumor suppressor gene
A gene whose inactivation leads to tumor development.
zygote
A fertilized egg.
zygotene
The stage of meiosis I during which homologous chromosomes become closely associated.
