Untitled Flashcards Set

p53

A crucial tumor suppressor involved in DNA repair, cell cycle regulation, and apoptosis, often mutated in cancers.

Li Fraumeni Syndrome

A rare inherited disorder caused by mutations in the TP53 gene, increasing cancer risk.

SV40 Large T Antigen

A viral protein that disrupts cellular regulatory pathways, particularly those involving tumor suppressors like p53.

Missense mutation

The majority type of p53 mutations that result in a single amino acid change in the protein.

Nonsense mutation

A mutation that introduces a premature stop codon in the p53 gene, leading to truncated protein.

Frameshift mutation

A mutation caused by insertions or deletions in the p53 gene that alters the reading frame.

Transactivation domain

The region of p53 that enables it to activate genes associated with DNA repair and cell cycle regulation.

Sequence-specific DNA binding domain

A hotspot for p53 mutations, crucial for the protein's ability to bind DNA.

Tetramerization domain

The domain necessary for p53 to form a tetramer, essential for its function.

Dominant negative mutation

A mutation in one allele of p53 that negatively affects the function of the normal allele.

MDM2

A negative feedback regulator that binds to p53, inhibiting its function and tagging it for degradation.

DNA damage

Caused by UV radiation, ionizing radiation, and oncogene signaling, impacting genomic integrity.

ATM

A protein kinase involved in the cellular response to DNA damage, particularly in double-strand breaks.

P21

An inhibitor of cyclin-dependent kinases, playing a role in cell cycle regulation and DNA repair.

ARF

A protein that inhibits MDM2 activity to stabilize p53.

Ink4A-Arf locus

Locus that encodes two proteins, contributing to cell cycle regulation and p53 stability.

E1A

An oncogenic signal that disrupts Rb function to push cells into the S phase of the cell cycle.

Apoptosis

An irreversible form of cell death regulated by p53 in response to cellular stress.

Phagocytic cell

Cells like macrophages that engulf and clear debris, secreting cytokines to modulate inflammation.

Necrosis

Accidental cell death due to damage, characterized by cell swelling and rupture.

Inflammation

A response to injury or infection which can also trigger apoptosis.

Extrinsic apoptosis pathway

Cell death pathway initiated by death ligands binding to receptors triggering caspase activation.

Death ligand (FASL)

A signal that binds to the death receptor to trigger apoptosis.

Death receptor (FAS)

Receptor that initiates the extrinsic apoptosis pathway upon binding with its ligand.

Caspases

Proteases that execute apoptosis; include initiators and executioners.

Pro-caspases

Inactive forms of caspases that must be cleaved to become active.

Lamin

A protein involved in nuclear structure, targeted by executioner caspases during apoptosis.

Actin

A structural protein that is cleaved during apoptosis by executioner caspases.

Membrane blebbing

A morphological change during apoptosis involving ballooning of the cell membrane.

ICAD

Inhibitor of Caspase-Activated DNase that prevents DNase from fragmenting DNA until apoptosis is triggered.

DNA laddering

A phenomenon resulting from the cleavage of DNA during apoptosis, visualized as distinct banding on gels.

Intrinsic apoptotic pathway

A cell death pathway triggered by internal stress signals like DNA damage.

Cytochrome C

A mitochondrial protein that plays a critical role in the intrinsic apoptosis pathway.

BCL-2

A protein that inhibits the intrinsic apoptosis pathway, promoting cell survival.

BCL-2 family

A group of proteins that regulate apoptosis either by promoting or inhibiting it.

APAF1

Apoptotic protease-activating factor 1, integral to the intrinsic apoptotic pathway.

Apoptosome 'wheel of death'

A complex formed during the apoptotic process that activates caspase-9.

Immortalization

The process of cells proliferating indefinitely, bypassing normal growth limitations.

Senescence

A state of permanent growth arrest in cells that are metabolically active.

End replication problem

Issues in replicating the ends of linear chromosomes, leading to telomere shortening.

RNA primer for DNA synthesis

Short RNA sequence required for DNA polymerase to initiate DNA synthesis.

Telomere

The protective end of a chromosome, composed of repetitive DNA sequences.

T-loop

A structure formed at the end of the telomere where single-stranded DNA folds back into the double-stranded region.

TRF1 and TRF2

Proteins that bind telomeres and are essential for their protection and maintenance.

POT1

Protector of telomeres; it binds to single-stranded telomeric DNA.

Tetrahymena

A ciliate that was crucial in the discovery of telomerase and the study of telomeres.

Telomerase

An enzyme that adds repetitive DNA sequences to telomeres, counteracting shortening.

hTERT

The catalytic subunit of telomerase responsible for adding telomeric DNA sequences.

hTR

Human telomerase RNA, serves as the template for telomerase activity.

Crisis

A state where cells escape senescence and start dying.

Breakage-fusion-bridge (BFB) cycle

A cycle in which chromosome breaks lead to fusions and subsequent problems during cell division.

Imetelstat

A drug that inhibits telomerase by binding to the RNA component of telomerase.

ALT

Alternative Lengthening of Telomeres, a telomere maintenance mechanism that does not involve telomerase.

Gene conversion

A type of genetic exchange occurring during homologous recombination.

Multi-step tumorigenesis

The process involving initiation, promotion, and progression of mutations leading to cancer.

Population doubling

The time required for a tumor to double in size or cell number.

Polyp

An abnormal tissue growth that can be a precursor to cancer, typically found in mucous membranes.

Polypectomy

The surgical removal of a polyp.

FAP

Familial Adenomatous Polyposis, a hereditary condition characterized by APC mutations.

APC

A tumor suppressor gene that regulates the Wnt signaling pathway, involved in colorectal cancer.

KRAS

A gene that encodes a protein involved in cellular signal transduction; mutations often lead to cancer.

SMADs

Proteins that transmit signals in the TGF-β signaling pathway.

Stem cells

Cells with the ability for self-renewal and differentiation into various specialized cells.

Driver mutation

A mutation that gives a growth advantage to cancer cells.

Passenger mutation

A mutation that occurs as a byproduct of cancer development without contributing to growth advantage.

Adenovirus E1A

A gene that inactivates tumor suppressors and promotes cell cycle progression.

SV40 small T Antigen

A viral protein that interacts with cellular regulators, influencing the cell cycle.

DNA polymerase

An enzyme that synthesizes new DNA strands and corrects errors during replication.

HNPCC/Lynch Syndrome

A genetic condition increasing colorectal cancer risk due to mismatch repair gene defects.

hMLH1

A protein involved in mismatch repair, part of the MutL complex.

hMSH2

A protein that recognizes mismatched base pairs during DNA replication.

Mismatch repair (MMR)

A system for correcting errors that occur during DNA replication.

Double strand DNA breaks

Severe DNA damage that requires specialized repair mechanisms.

Ionizing radiation

Energy that causes DNA damage, particularly double-strand breaks.

Homology directed repair (HDR)

A precise DNA repair mechanism that uses a homologous template.

BRCA1/BRCA2

Genes that are crucial for HDR; mutations increase breast and ovarian cancer risk.

RAD51

A protein that facilitates strand invasion during homologous recombination.

ATM

A protein kinase that activates DNA repair pathways upon detecting DNA damage.

Mary Claire King

The scientist who discovered BRCA1.

Sister chromatid

Identical copies of a chromosome formed during DNA replication.

5’ 3’ exonuclease

An enzyme activity involved in DNA repair by removing damaged nucleotides.

Nonhomologous End Joining (NHEJ)

A DNA repair mechanism that fixes double-strand breaks without a homologous template.

Errors in DNA replication

Mistakes such as mismatched bases and strand breaks that can lead to mutations.

Endogenous biochemical processes

Natural cellular processes that can cause DNA mutations, such as oxidation and deamination.

Physical mutagen

Agents like radiation that cause direct damage to DNA.

X-Ray

A form of ionizing radiation that can induce DNA damage.

UV radiation

Causes DNA damage, primarily by forming pyrimidine dimers.

Nucleotide Excision Repair (NER)

A DNA repair mechanism that removes bulky lesions caused by UV light.

Xeroderma Pigmentosum (XP)

A genetic disorder resulting from NER defects, leading to increased UV sensitivity.

XPC and XPE

Proteins involved in recognizing and binding to DNA damage in the NER pathway.

XPB and XPD

Helicases that unwind DNA around lesions during NER.

XPF and XPG

Endonucleases that excise damaged DNA bases.

DNA polymerase (epsilon)

An enzyme involved in DNA synthesis with proofreading capabilities.

Error-free bypass

A process where DNA polymerases bypass damage without introducing mutations.

DNA polymerase (eta)

A polymerase that inserts adenine opposite a pyrimidine dimer.

Error-prone bypass

A process that allows DNA polymerases to replicate across damaged DNA without accurate repair.

DNA polymerase (zeta)

A polymerase that places random nucleotides across from damaged DNA.

Alkylation

The addition of an alkyl group to DNA, potentially causing mutations.

MGMT

A DNA repair protein that removes alkyl groups from guanine to prevent mutations.

Base Excision Repair (BER)

A mechanism that repairs small, non-helix-distorting DNA lesions.