In the field of
molecular biology
Molecular biology is the branch of biology that seeks to understand the molecular basis of biological activity in and between cells, including biomolecular synthesis, modification, mechanisms, and interactions. The study of chemical and physi ...
, ''trans''-acting (''trans''-regulatory, ''trans''-regulation), in general, means "acting from a different molecule" (''i.e.'',
intermolecular
An intermolecular force (IMF) (or secondary force) is the force that mediates interaction between molecules, including the electromagnetic forces of attraction
or repulsion which act between atoms and other types of neighbouring particles, e.g. a ...
). It may be considered the opposite of
''cis''-acting (''cis''-regulatory, ''cis''-regulation), which, in general, means "acting from the same molecule" (''i.e.'',
intramolecular).
In the context of
transcription
Transcription refers to the process of converting sounds (voice, music etc.) into letters or musical notes, or producing a copy of something in another medium, including:
Genetics
* Transcription (biology), the copying of DNA into RNA, the fir ...
regulation, a ''trans''-acting factor is usually a regulatory
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...
that binds to
DNA. The binding of a ''trans''-acting factor to a ''cis''-regulatory element in
DNA can cause changes in transcriptional expression levels.
microRNAs
MicroRNA (miRNA) are small, single-stranded, non-coding RNA molecules containing 21 to 23 nucleotides. Found in plants, animals and some viruses, miRNAs are involved in RNA silencing and post-transcriptional regulation of gene expression. miR ...
or other diffusible molecules are also examples of ''trans''-acting factors that can regulate target sequences.
The ''trans''-acting gene may be on a different
chromosome
A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins are ...
to the target gene, but the activity is via the intermediary protein or RNA that it encodes.
''Cis''-acting elements, on the other hand, do not code for protein or RNA. Both the ''trans''-acting gene and the protein/RNA that it encodes are said to "act in ''trans''" on the target gene.
See also
*
Trans-regulatory element Trans-regulatory elements (TRE) are DNA sequences encoding upstream regulators (ie. trans-acting factors), which may modify or Regulation of gene expression, regulate the expression of distant genes. Trans-acting factors interact with Cis-regulatory ...
*
Transactivation In the context of gene regulation: transactivation is the increased rate of gene expression triggered either by biological processes or by artificial means, through the expression of an intermediate transactivator protein.
In the context of recep ...
*
Transrepression In the field of molecular biology, transrepression is a process whereby one protein represses (i.e., inhibits) the activity of a second protein through a protein-protein interaction. Since this repression occurs between two different protein molecu ...
References
Genetics terms
Molecular biology
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