In genetics, complementary DNA (cDNA) is DNA synthesized from a single-stranded RNA template in a reaction catalyzed by the enzyme reverse transcriptase. cDNA is often used to clone eukaryotic genes in prokaryotes. When scientists want to express a specific protein in a cell that does not normally express that protein, they will transfer the cDNA that codes for the protein to the recipient cell. In molecular biology, cDNA is also generated to analyze transcriptomic profiles in bulk tissue, single cells, or single nuclei in assays such as microarrays and RNA-seq.
A telomere is a region of repetitive nucleotide sequences associated with specialized proteins at the ends of linear chromosomes. Although there are different architectures, telomeres, in a broad sense, are a widespread genetic feature most commonly found in eukaryotes. In most, if not all species possessing them, they protect the terminal regions of chromosomal DNA from progressive degradation and ensure the integrity of linear chromosomes by preventing DNA repair systems from mistaking the very ends of the DNA strand for a double strand break.
Telomerase, also called terminal transferase, is a ribonucleoprotein that adds a species-dependent telomere repeat sequence to the 3' end of telomeres. A telomere is a region of repetitive sequences at each end of the chromosomes of most eukaryotes. Telomeres protect the end of the chromosome from DNA damage or from fusion with neighbouring chromosomes. The fruit fly Drosophila melanogaster lacks telomerase, but instead uses retrotransposons to maintain telomeres.
Elizabeth Helen Blackburn, is an Australian-American Nobel laureate who is the former president of the Salk Institute for Biological Studies. Previously she was a biological researcher at the University of California, San Francisco, who studied the telomere, a structure at the end of chromosomes that protects the chromosome. In 1984, Blackburn co-discovered telomerase, the enzyme that replenishes the telomere, with Carol W. Greider. For this work, she was awarded the 2009 Nobel Prize in Physiology or Medicine, sharing it with Greider and Jack W. Szostak, becoming the first Australian woman Nobel laureate. She also worked in medical ethics, and was controversially dismissed from the Bush administration's President's Council on Bioethics.
Thomas Robert Cech is an American chemist who shared the 1989 Nobel Prize in Chemistry with Sidney Altman, for their discovery of the catalytic properties of RNA. Cech discovered that RNA could itself cut strands of RNA, suggesting that life might have started as RNA. He also studied telomeres, and his lab discovered an enzyme, TERT, which is part of the process of restoring telomeres after they are shortened during cell division. As president of Howard Hughes Medical Institute, he promoted science education, and he teaches an undergraduate chemistry course at the University of Colorado.
The Hayflick limit, or Hayflick phenomenon, is the number of times a normal somatic, differentiated human cell population will divide before cell division stops. However, this limit does not apply to stem cells.
Michael D. West is an American biogerontologist, and a pioneer in stem cells, cellular aging and telomerase. He is the founder and CEO of AgeX Therapeutics, a startup focused on the field of experimental gerontology.
Dyskeratosis congenita (DKC),also known as Zinsser-Engman-Cole syndrome, is a rare progressive congenital disorder with a highly variable phenotype. The entity was classically defined by the triad of abnormal skin pigmentation, nail dystrophy, and leukoplakia of the oral mucosa, but these components do not always occur. DKC is characterized by short telomeres. Some of the manifestations resemble premature ageing. The disease initially mainly affects the skin, but a major consequence is progressive bone marrow failure which occurs in over 80%, causing early mortality.
Children's Medical Research Institute (CMRI) is an Australian-based independent medical research institute located in Westmead, Sydney NSW that conducts research into children's genetic diseases. As of 2019, current research is focused on cancer, birth defects, neurological conditions such as epilepsy, and gene therapy to treat genetic diseases. CMRI created and continues to operate Australia's Jeans for Genes fundraising campaign.
Carolyn Widney Greider is an American molecular biologist and Nobel laureate. She joined the University of California, Santa Cruz as a Distinguished Professor in the department of molecular, cell, and developmental biology in October 2020.
Telomerase reverse transcriptase is a catalytic subunit of the enzyme telomerase, which, together with the telomerase RNA component (TERC), comprises the most important unit of the telomerase complex.
Telomerase RNA component, also known as TR, TER or TERC, is an ncRNA found in eukaryotes that is a component of telomerase, the enzyme used to extend telomeres. TERC serves as a template for telomere replication by telomerase. Telomerase RNAs differ greatly in sequence and structure between vertebrates, ciliates and yeasts, but they share a 5' pseudoknot structure close to the template sequence. The vertebrate telomerase RNAs have a 3' H/ACA snoRNA-like domain.
Telomerase protein component 1 is an enzyme that in humans is encoded by the TEP1 gene.
PIN2/TERF1-interacting telomerase inhibitor 1, also known as PINX1, is a human gene. PINX1 is also known as PIN2 interacting protein 1. PINX1 is a telomerase inhibitor and a possible tumor suppressor.
Cycloastragenol is a triterpenoid isolated from various legume species in the genus Astragalus that is purported to have telomerase activation activity. A preliminary in vitro study on human CD4 and CD8 T cells found that cycloastragenol may moderately increase telomerase activity and inhibit the onset of cellular senescence.
William Henry Andrews is an American molecular biologist and gerontologist whose career has centered on searching for a cure for human aging. Andrews is the founder and president of the biotechnology company Sierra Sciences. In the 1990s, he led the team at Geron Corporation that was the first to successfully identify the genes for human enzyme telomerase. This enzyme is responsible for preventing telomeres from shortening in human primordial germ cells.
Telomeric repeat–containing RNA (TERRA) is a long non-coding RNA transcribed from telomeres - repetitive nucleotide regions found on the ends of chromosomes that function to protect DNA from deterioration or fusion with neighboring chromosomes. TERRA has been shown to be ubiquitously expressed in almost all cell types containing linear chromosomes - including humans, mice, and yeasts. While the exact function of TERRA is still an active area of research, it is generally believed to play a role in regulating telomerase activity as well as maintaining the heterochromatic state at the ends of chromosomes. TERRA interaction with other associated telomeric proteins has also been shown to help regulate telomere integrity in a length-dependent manner.
María Antonia Blasco Marhuenda, known as María Blasco, is a Spanish molecular biologist. She is the current director of the Spanish National Cancer Research Centre.
Bryant Villeponteau is an American scientist, entrepreneur, and longevity expert who has worked in both academia and industry.
Kathleen Collins is an American biophysicist and Professor at the University of California, Berkeley. Her research considers telomerase RNA structure and telomere function. In 2020 she was elected a Fellow of the American Academy of Arts and Sciences.
