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Acetylated
Addition of acetyl groups to proteins. On histones, the addition of acetyl groups to a lysine residue.
Anaphase
Stage of mitosis when chromosomes separate. Chromatids move to opposite poles of the cell (opposite ends of the nuclear spindle).
Apoptosis
A type of cell death in which a series of molecular steps in a cell leads to its death. This is the body's normal way of getting rid of unneeded or abnormal cells. The process of apoptosis may be blocked in cancer cells. Also called programmed cell death.
Cancer
A term for diseases in which abnormal cells divide without control. Cancer cells can invade nearby tissues and can spread through the bloodstream and lymphatic system to other parts of the body. There are several main types of cancer, including carcinoma, sarcoma, leukemia, and lymphoma.
Cell cycle
Sequence of stages that a cell passes through between one cell division and the next. The cell cycle can be divided into 4 main stages, G1, S, G2, and M.
Cell cycle checkpoints
A surveillance system responsible for monitoring the proper completion of an event within a cell. Checkpoints control the order and timing of cell cycle transitions and ensure that critical events, such as DNA replication and chromosome segregation, are completed with high fidelity.
Centromere
The central portion of the chromosome to which the spindle fibers attach during mitotic division.
Chromatin
Fibers made up of DNA, RNA, and protein that form the chromosomes.
Chromatin remodeling
Modification of chromatin structure by acetylation, phosphorylation, and methylation. This process controls gene expression by regulating the accessibility of DNA to transcription factors.
Chromosome
One of the bodies (normally 46 in somatic cells in humans) in the cell nucleus that is the bearer of genes and has the form of a delicate chromatin filament during interphase. It contracts to form a compact cylinder segmented into 2 arms by the centromere during metaphase and anaphase stages of cell division, and is capable of reproducing its physical and chemical structure through successive cell divisions.
CIP/KIP
A cyclin-dependent kinase inhibitor family.
Cyclin-dependent kinase (Cdk)
A protein kinase involved in regulation of the cell cycle. A cyclin-dependent kinase is activated by association with a cyclin, forming a cyclin-dependent kinase complex.
Cyclin-dependent kinase inhibitors
Proteins that inhibit the actions of cyclin-dependent kinases.
Cyclins
Molecules that help control the cell cycle. There are multiple cyclins, each with a specific role. Cyclins function as ON switches for the active phase of the cell cycle.
Deoxyribonucleic acid (DNA)
Considered to be the autoreproducing component of chromosomes and of many viruses, and the repository of hereditary characteristics. Nucleic acid containing deoxyribose as the sugar component and found principally in the nuclei (chromatin, chromosomes) of animals. DNA is usually loosely bound to protein. Chromosomes are composed of double-stranded DNA; mitochondrial DNA is circular.
Deregulated expression
Expression of a gene that is no longer under proper control.
Differentiation
The process by which cells become progressively more specialized; a normal process through which cells mature. In cancer, differentiation refers to how mature (developed) the cancer cells are in a tumor. Differentiated tumor cells resemble normal cells and tend to grow and spread at a slower rate than undifferentiated or poorly differentiated tumor cells, both of which lack the structure and function of normal cells and grow uncontrollably.
DNA methylation
Inactivation of genes by the addition of methyl (CH3-) groups to cytosine.
Epigenetic
Inheritable information encoded by modifications of the genome and chromatin components that affects gene expression. It does not include changes in the base sequences of DNA.
Epigenetic silencing
The silencing (turning down or off) of gene transcription by modifications to the genome and chromatin components.
Eukaryotic
Pertaining to or characteristic of a eukaryote, a cell containing a membrane-bound nucleus containing chromosomes of DNA, RNA, and proteins.
G1
Period of the cell cycle that represents the gap between the completion of mitosis and the beginning of DNA replication.
G2
Period of the cell cycle that represents the gap between the completion of DNA synthesis and the beginning of mitosis.
Gene expression
The translation of information encoded in a gene into protein or RNA.
Genetics
Branch of science concerned with the means and consequences of transmission and generation of the components of biologic inheritance.
Genome
The complete set of chromosomes in an individual.
Histone acetyltransferase (HAT)
A protein that acetylates core histones, which results in important regulatory effects on chromatin structure and assembly and on gene transcription.
Histone deacetylase (HDAC)
An enzyme that removes an acetyl group from histones, which allows histones to bind DNA and inhibit gene transcription.
Histone modifications
Changes to the structure of the histones that can serve to alter the transcription of genes.
Histones
Basic proteins with chromatid that bind DNA at regular intervals.
Hyperacetylation
A state in which acetylation of histone core proteins has occurred that results in altered gene function.
Kinase
An enzyme that transfers phosphate groups to a protein at serine, threonine, or tyrosine amino acids.
M stage
The stage of the cell cycle in which the process of mitosis takes place in the nucleus of a dividing cell and results in the formation of 2 new nuclei, each having the same number of chromosomes as the parent nucleus. Cell division.
Malignant
Term used to describe a cancerous tumor that generally grows rapidly and is capable of spreading throughout the body. The term malignancy is sometimes used interchangeably with the term cancer.
Messenger RNA (mRNA)
Form of RNA that carries the genetic code for a particular protein from the DNA in the cell's nucleus to a ribosome in the cytoplasm and acts as a template, or pattern, for the formation of that protein.
Metaphase
Stage of mitosis in the eukaryotic cell cycle in which condensed chromosomes align in the middle of the cell before being separated into each of the 2 daughter cells.
Nucleosome
The fundamental structural unit of eukaryotic chromosomes. It consists of pairs of each of the core histones (H2A, H2B, H3, and H4, thereby creating the histone octamer) and a single molecule of the linker histone H1.
Octamer
A protein (polymer) made up of 8 units.
Oncogene
A gene that normally directs cell growth. If altered, an oncogene can allow or promote the uncontrolled growth of cancer. Alterations can be inherited or caused by an environmental exposure to carcinogens.
p21
A member of the CIP/KIP family of cyclin-dependent kinase inhibitors, also known as p21waf/cip1.
p53
Also known as TP53 or tumor protein 53 is a gene that codes for a protein that regulates the cell cycle, thereby functioning as a tumor suppressor.
Programmed cell death
A type of cell death in which a series of molecular steps in a cell leads to its death. This is the body's normal way of getting rid of unneeded or abnormal cells. The process of programmed cell death may be blocked in cancer cells. Also called apoptosis.
Protein
Large molecules composed of 1 or more chains of amino acids in a specific order; the order is determined by the base sequence of nucleotides in the gene coding for the protein. Proteins are required for the structure, function, and regulation of the body's cells, tissues, and organs, and each protein has unique functions. Examples are hormones, enzymes, and antibodies.
Ribonucleic acid (RNA)
Single-stranded nucleic acid (similar to the double-stranded nucleic acid DNA) that contains the sugar ribose (DNA contains deoxyribose). There are many forms of RNA, including messenger RNA, transfer RNA, and ribosomal RNA, all involved in protein synthesis.
S phase
The phase of the cell cycle in which DNA synthesis occurs, also referred to as the synthetic phase.
Transcription
Transfer of genetic code information from DNA to RNA. DNA-directed RNA synthesis.
Transcription factors
Proteins that assemble on the promoter region of DNA to guide and stabilize the binding of RNA polymerase and are required to initiate transcription.
Transcriptional silencing
The repression of gene transcription.
Transfer RNA
RNA molecules that carry amino acids to sites on ribosomes where proteins are synthesized.
Translation
The complex process by which messenger RNA, transfer RNA, and ribosomes produce protein from amino acids, the specificity of synthesis being controlled by the base sequences of the messenger RNA.
Tumorigenesis
Production of a new cancerous growth or growths.
Tumor suppressor genes
Genes that slow down cell division or cause cells to die at the appropriate time. Alterations of these genes can lead to too much cell growth and development of cancer.
