In the field of
molecular biology
Molecular biology is a branch of biology that seeks to understand the molecule, molecular basis of biological activity in and between Cell (biology), cells, including biomolecule, biomolecular synthesis, modification, mechanisms, and interactio ...
, ''trans''-acting (''trans''-regulatory, ''trans''-regulation), in general, means "acting from a different molecule" (''i.e.'',
intermolecular). 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 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 residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...
that binds to
DNA
Deoxyribonucleic acid (; DNA) is a polymer composed of two polynucleotide chains that coil around each other to form a double helix. The polymer carries genetic instructions for the development, functioning, growth and reproduction of al ...
. The binding of a ''trans''-acting factor to a ''cis''-regulatory element in
DNA
Deoxyribonucleic acid (; DNA) is a polymer composed of two polynucleotide chains that coil around each other to form a double helix. The polymer carries genetic instructions for the development, functioning, growth and reproduction of al ...
can cause changes in transcriptional expression levels.
microRNAs 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 package of DNA containing part or all of the genetic material of an organism. In most chromosomes, the very long thin DNA fibers are coated with nucleosome-forming packaging proteins; in eukaryotic cells, the most import ...
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.
Transcription factors are categorized as trans-acting factors.
See also
*
Trans-regulatory element
*
Transactivation
*
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 terminology
Molecular biology
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