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 phys ...

, ''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 residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...

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 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 ar ...

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.

References

Genetics terms Molecular biology {{biochem-stub

See also

References