Transcription

Definition

The enzymatic synthesis of a complementary RNA strand from a DNA template, representing the first step of gene expression. In arthropods, transcription is regulated by transcription factors, hormones such as ecdysone, and environmental cues, controlling development, metamorphosis, diapause, and the production of specialized proteins including venoms, pheromones, and cuticular components.

Etymology

Latin transcribere, from trans- (across) + scribere (to write)

Example

In the silk moth Bombyx mori, transcription of fibroin genes is activated during the fifth instar by ecdysone-responsive transcription factors, enabling massive production of silk protein prior to pupation.

Synonyms

• RNA synthesis
• DNA-dependent RNA synthesis

Related Terms

• translation
• Gene expression
• transcription factor
• Ecdysone
• reverse transcription
• mRNA
• promoter
• RNA polymerase

Usage Notes

Distinguish from reverse transcription (RNA→DNA, as in retrotransposons or viral replication) and from the unrelated linguistic or musical sense of recording spoken or performed content. In functional genomics studies of insects and arachnids, 'transcriptional profiling' refers to measuring which genes are actively transcribed under specific conditions, such as immune challenge or desiccation stress.