Trans-acting

In the field of molecular biology, '''''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 that binds to DNA.<ref>{{cite book |last1=Brooker |first1=Robert J |title=Genetics: analysis and principles |publisher=McGraw-Hill Education |location=New York, NY |edition=6th}}</ref> 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.<ref>{{cite book | last = Watson | first = James D. |author2=Caudy, Amy A |author3=Myers, Richard M. |author4=Witkowski, Jan A. | authorlink = James D. Watson | title = Recombinant DNA: Genes and Genomes - A Short Course | publisher = Cold Spring Harbor Press | year = 2007 | pages = 57–58 | isbn = 978-0-7167-2866-5 }}</ref> The ''trans''-acting gene may be on a different chromosome 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

==References== {{reflist}}

Category:Genetics terminology Category:Molecular biology