A retrovirus is a type of virus that inserts a DNA copy of its RNA genome into the DNA of a host cell that it invades, thus changing the genome of that cell. After invading a host cell's cytoplasm, the virus uses its own reverse transcriptase enzyme to produce DNA from its RNA genome, the reverse of the usual pattern, thus retro (backwards). The new DNA is then incorporated into the host cell genome by an integrase enzyme, at which point the retroviral DNA is referred to as a provirus. The host cell then treats the viral DNA as part of its own genome, transcribing and translating the viral genes along with the cell's own genes, producing the proteins required to assemble new copies of the virus. Many retroviruses cause serious diseases in humans, other mammals, and birds.
Heterochromatin is a tightly packed form of DNA or condensed DNA, which comes in multiple varieties. These varieties lie on a continuum between the two extremes of constitutive heterochromatin and facultative heterochromatin. Both play a role in the expression of genes. Because it is tightly packed, it was thought to be inaccessible to polymerases and therefore not transcribed; however, according to Volpe et al. (2002), and many other papers since, much of this DNA is in fact transcribed, but it is continuously turned over via RNA-induced transcriptional silencing (RITS). Recent studies with electron microscopy and OsO4 staining reveal that the dense packing is not due to the chromatin.
Alternative splicing, or alternative RNA splicing, or differential splicing, is an alternative splicing process during gene expression that allows a single gene to code for multiple proteins. In this process, particular exons of a gene may be included within or excluded from the final, processed messenger RNA (mRNA) produced from that gene. This means the exons are joined in different combinations, leading to different (alternative) mRNA strands. Consequently, the proteins translated from alternatively spliced mRNAs usually contain differences in their amino acid sequence and, often, in their biological functions.
Adenoviruses are medium-sized, nonenveloped viruses with an icosahedral nucleocapsid containing a double-stranded DNA genome. Their name derives from their initial isolation from human adenoids in 1953.
Ronald Mark Evans is an American Biologist, Professor and Head of the Salk’s Gene Expression Laboratory, and the March of Dimes Chair in Molecular and Developmental Biology at the Salk Institute for Biological Studies in La Jolla, California and a Howard Hughes Medical Institute Investigator. Dr. Ronald M. Evans is known for his original discoveries of nuclear hormone receptors (NR), a special class of transcriptional factor, and the elucidation of their universal mechanism of action, a process that governs how lipophilic hormones and drugs regulate virtually every developmental and metabolic pathway in animals and humans. Nowadays, NRs are among the most widely investigated group of pharmaceutical targets in the world, already yielding benefits in drug discovery for cancer, muscular dystrophies, osteoporosis, type II diabetes, obesity, and cardiovascular diseases. His current research focuses on the function of nuclear hormone signaling and their function in metabolism and cancer.
An epigenome consists of a record of the chemical changes to the DNA and histone proteins of an organism; these changes can be passed down to an organism's offspring via transgenerational stranded epigenetic inheritance. Changes to the epigenome can result in changes to the structure of chromatin and changes to the function of the genome.
Robert G. Roeder is an American biochemist. He is known as a pioneer scientist in eukaryotic transcription. He discovered three distinct nuclear RNA polymerases in 1969 and characterized many proteins involved in the regulation of transcription, including basic transcription factors and the first mammalian gene-specific activator over five decades of research. He is the recipient of the Gairdner Foundation International Award in 2000, the Albert Lasker Award for Basic Medical Research in 2003, and the Kyoto Prize in 2021. He currently serves as Arnold and Mabel Beckman Professor and Head of the Laboratory of Biochemical and Molecular Biology at The Rockefeller University.
The murine leukemia viruses are retroviruses named for their ability to cause cancer in murine (mouse) hosts. Some MLVs may infect other vertebrates. MLVs include both exogenous and endogenous viruses. Replicating MLVs have a positive sense, single-stranded RNA (ssRNA) genome that replicates through a DNA intermediate via the process of reverse transcription.
Gene delivery is the process of introducing foreign genetic material, such as DNA or RNA, into host cells. Gene delivery must reach the genome of the host cell to induce gene expression. Successful gene delivery requires the foreign gene delivery to remain stable within the host cell and can either integrate into the genome or replicate independently of it. This requires foreign DNA to be synthesized as part of a vector, which is designed to enter the desired host cell and deliver the transgene to that cell's genome. Vectors utilized as the method for gene delivery can be divided into two categories, recombinant viruses and synthetic vectors.
Chromatin remodeling is the dynamic modification of chromatin architecture to allow access of condensed genomic DNA to the regulatory transcription machinery proteins, and thereby control gene expression. Such remodeling is principally carried out by 1) covalent histone modifications by specific enzymes, e.g., histone acetyltransferases (HATs), deacetylases, methyltransferases, and kinases, and 2) ATP-dependent chromatin remodeling complexes which either move, eject or restructure nucleosomes. Besides actively regulating gene expression, dynamic remodeling of chromatin imparts an epigenetic regulatory role in several key biological processes, egg cells DNA replication and repair; apoptosis; chromosome segregation as well as development and pluripotency. Aberrations in chromatin remodeling proteins are found to be associated with human diseases, including cancer. Targeting chromatin remodeling pathways is currently evolving as a major therapeutic strategy in the treatment of several cancers.
Simon Joseph Boulton is a British scientist who has made important contributions to the understanding of DNA repair and the treatment of cancer resulting from DNA damage. He currently occupies the position of Senior Scientist and group leader of the DSB Repair Metabolism Laboratory at the Francis Crick Institute, London. He is also an honorary Professor at University College London.
Murine polyomavirus is an unenveloped double-stranded DNA virus of the polyomavirus family. The first member of the family discovered, it was originally identified by accident in the 1950s. A component of mouse leukemia extract capable of causing tumors, particularly in the parotid gland, in newborn mice was reported by Ludwik Gross in 1953 and identified as a virus by Sarah Stewart and Bernice Eddy at the National Cancer Institute, after whom it was once called "SE polyoma". Stewart and Eddy would go on to study related polyomaviruses such as SV40 that infect primates, including humans. These discoveries were widely reported at the time and formed the early stages of understanding of oncoviruses.
An R-loop is a three-stranded nucleic acid structure, composed of a DNA:RNA hybrid and the associated non-template single-stranded DNA. R-loops may be formed in a variety of circumstances and may be tolerated or cleared by cellular components. The term "R-loop" was given to reflect the similarity of these structures to D-loops; the "R" in this case represents the involvement of an RNA moiety.
Anthony Rex Hunter is a British-American biologist who is a professor of biology at the Salk Institute for Biological Studies and the University of California San Diego. His research publications list his name as Tony Hunter.
A topologically associating domain (TAD) is a self-interacting genomic region, meaning that DNA sequences within a TAD physically interact with each other more frequently than with sequences outside the TAD. The median size of a TAD in mouse cells is 880 kb, and they have similar sizes in non-mammalian species. Boundaries at both side of these domains are conserved between different mammalian cell types and even across species and are highly enriched with CCCTC-binding factor (CTCF) and cohesin. In addition, some types of genes appear near TAD boundaries more often than would be expected by chance.
Maurice Green was an American virologist. He is regarded as a pioneer in the study of animal viruses, in particular their role in cancer. Green founded the Institute of Molecular Virology at St. Louis University School of Medicine in the late 1950s, and later served as its chairman.
Diana Hargreaves is an American biologist and assistant professor at The Salk Institute for Biological Studies and member of The Salk Cancer Center. Her laboratory focuses on epigenetic regulation by the BAF (SWI/SNF) chromatin remodeling complexes in diverse physiological processes including development, immunity, and diseases such as cancer.
Kelly A Frazer is a Professor of Pediatrics in the Medical School at the University of California, San Diego, Chief of the Division of Genome Information Sciences and Director of the Institute for Genomic Medicine.
Paolo Sassone-Corsi was an Italian molecular biologist, epigeneticist, and researcher. He is known for his contributions in the areas of transcriptional regulation, epigenetics, circadian biology, and metabolic regulation. He is known for his contributions in the areas of transcriptional regulation, epigenetics, circadian biology, and metabolic regulation. His research primarily focused on the mechanisms that regulate transcription and their relation to metabolism and circadian clocks. His work focused on understanding how the circadian clock regulates metabolic cycles. Most notably, he discovered that SIRT1, a histone deacetylase with a critical role in gene expression and metabolism, is able to regulate the activity of the CLOCK protein. In 2011, Sassone-Corsi founded and directed the “Center for Epigenetics and Metabolism” at the University of California, Irvine.
Jan Karlseder is an Austrian molecular biologist, a professor in the Molecular and Cellular Biology Laboratory, the Director of the Paul F. Glenn Center for Biology of Aging Research and the holder of the Donald and Darlene Shiley Chair at the Salk Institute for Biological Studies.
