- gene conversion
A DNA recombination process that results in the unidirectional transfer of genetic material from a donor sequence to a highly homologous acceptor.
- gene looping
The formation and maintenance of DNA loops that juxtapose sequentially separated regions of RNA polymerase II-transcribed genes.
- gene silencing
Any process carried out at the cellular level that results in either long-term transcriptional repression via action on chromatin structure or RNA mediated, post-transcriptional repression of gene expression.
- gene expression
The process in which a gene's sequence is converted into a mature gene product or products (proteins or RNA). This includes the production of an RNA transcript as well as any processing to produce a mature RNA product or an mRNA or circRNA (for protein-coding genes) and the translation of that mRNA or circRNA into protein. Protein maturation is included when required to form an active form of a product from an inactive precursor form.
- meiotic gene conversion
The cell cycle process in which genetic information is transferred from one helix to another. It often occurs in association with general genetic recombination events, and is believed to be a straightforward consequence of the mechanisms of general recombination and DNA repair. For example, meiosis might yield three copies of the maternal version of an allele and only one copy of the paternal allele, indicating that one of the two copies of the paternal allele has been changed to a copy of the maternal allele.
- virus induced gene silencing
Specific posttranscriptional gene inactivation ('silencing') both of viral gene(s), and host gene(s) homologous to the viral genes. This silencing is triggered by viral infection, and occurs through a specific decrease in the level of mRNA of both host and viral genes.
- tRNA gene clustering
The process in which tRNA genes, which are not linearly connected on the chromosome, are transported in three dimensions to, and maintained together in, the nucleolus. This clustered positioning leads to transcriptional silencing of nearby RNA polymerase II promoters (termed tRNA gene mediated (tgm) silencing) in S. cerevisiae.
- viral gene expression
A process by which a viral gene is converted into a mature gene product or products (proteins or RNA). This includes viral transcription, processing to produce a mature RNA product, and viral translation.
- short tract gene conversion
A gene conversion process in which a segment of about 50-200 base pairs is transferred from the donor to the acceptor.
- gene silencing by miRNA
Downregulation of gene expression through the action of microRNAs (miRNAs), endogenous 21-24 nucleotide small RNAs processed from stem-loop RNA precursors (pre-miRNAs). Once incorporated into a RNA-induced silencing complex (RISC), miRNAs can downregulate gene expression by either of two posttranscriptional mechanisms: endolytic cleavage of mRNA cleavage or translational repression, usually accompanied by poly-A tail shortening and subsequent degradation of the mRNA.