Final Exam Vocabulary

Vulval Precursor Cells (VPCs)

Six hypodermal cells, consecutively numbered P3p through P8p, each of which has the potential to contribute cells to the v*lva

Anchor Cell

A cell in nematodes that is important in the development of the reproductive system, as it is required for the production of the tube of cells that allows embryos to pass from the uterus through the v*lva to the outside of the worm

Equivalence Group

Group of cells with the same potential that acquire their final fates through cell to cell interactions

V*lvaless

A mutant C. elegan phenotype where no v*lva develops in the body of the worm

Multiv*lva

A mutant C. elegan phenotype where multiple pseudov*lvas form in the body of the worm along with the wild-type one

Null Mutation

A loss-of-function mutation

Hypermorph Mutation

A gain-of-function mutation

Epistasis

Type of gene interaction where a gene at one locus masks or suppresses the effects of a gene at a different locus

LIN-3

A gene expressed in the anchor cell that encodes a growth factor-like molecule to induce a primary fate in the VPC closest to it

LET-23

A gene that encodes an EGF receptor-like molecule to receive the lateral signal from the primary VPC

LET-60

A gene that encodes a Ras protein

LIN-12

Encodes a conserved transmembrane receptor of the Notch family

Signaling Fate

A cell fate where a cell is induced to be producing the ligand

Receiving Fate

A cell fate where a cell is induced to be expressing the receptor

Stochastic Event

A random event, involving chance, probability, or random variables

Cell Cycle

The orderly sequence of events by which a cell duplicates its chromosomes and, usually, the other cell contents, and divides into two

G1 Phase

Gap 1 phase of the eukaryotic cell-division cycle, between the end of mitosis and the start of DNA synthesis

G2 Phase

Gap 2 phase of the eukaryotic cell-division cycle, between the end of DNA synthesis and the beginning of mitosis

Mitosis

The nuclear division that occurs during the proliferation of somatic diploid cells, and results in both daughter cells having the same diploid complement of chromosomes as the parent cell

Cytokinesis

Division of the cytoplasm of a plant or animal cell into two

Cyclin

Protein that (periodically rises and falls in concentration in step with the eukaryotic cell cycle) activates crucial protein kinases (Cdks) and thereby helps control the progression from one stage of the cell cycle to the next

Cyclin-Dependent Kinase (Cdk)

Protein kinase that has to be complexed with a cyclin protein in order to act

Cyclin-Cdk Complex

Protein complex formed periodically during the eukaryotic cell cycle as the level of a particular cyclin increases, thereby partially activating Cdk

Fission

The division of a single entity into two or more parts and the regeneration of those parts to separate entities resembling the original

Budding

A form of asexual reproduction where a new individual develops from some generative anatomical point of the parent organism

Maturation Promoting Factor (MPF)

Stimulates the mitotic and meiotic phases of the cell cycle

Cdk-Activating Kinase (CAK)

Protein kinase that phosphorylates Cdks in cyclin-Cdk complexes, activating Cdk

G1 Cyclin

Cyclin present in the G1 phase of the eukaryotic cell cycle that forms complexes with Cdks that help govern the activity of the G1/S-cyclins

Anaphase-Promoting Complex (APC/C)

Ubiquitin ligase that catalyzes the ubiquitylation and destruction of securin and M- and S-cyclins, initiating the separation of sister chromatids in the metaphase-to-anaphase transition during mitosis

G1/S-Cyclin

Cyclin that activates Cdks in late G1 of the eukaryotic cell cycle and thereby helps trigger progression through Start, resulting in a commitment to cell-cycle entry

S-Cyclin

A cyclin that helps stimulate DNA replication and chromosome duplication

M-Cyclin

A cyclin found in all eukaryotic cells that promotes the events of mitosis

Wee1

Protein kinase that inhibits Cdk activity by phosphorylating amino acids in the Cdk active site

Proteasome

A large protein complex that degrades proteins marked with ubiquitin polypeptides

cdc25

Protein phosphatase that dephosphorylates Cdks and increases their activity

Nuclear Lamin

Protein subunit of the intermediate filaments that form the nuclear lamina

Nuclear Lamina

Fibrous meshwork of proteins on the inner surface of the inner nuclear membrane

p27

Binds and inhibits cyclin-Cdk to arrest the cell cycle

Cyclin D

A regulatory protein that forms a complex with Cdk4/6 to promote cell cycle progression

Rb

Cell cycle inhibitor to E2F and turns on S-phase (start/re-entry of the cell cycle)

E2F Protein

Transcription regulatory protein that switches on many genes that encode proteins required for entry into the S phase of the cell cycle

Cdk Inhibitor (CKI)

A protein that interacts with a cyclin-CDK complex to block kinase activity, usually during G1 or in response to signals from the environment or from damaged DNA

p53

A transcription regulatory gene that is activated by damage to the DNA and is involved in blocking further progression through the cell cycle

p16

A CKI that inhibits the formation of the cyclin D1/Cdk4 complex

Mitogen

Extracellular signal molecule that stimulates cells to prolif