transcriptionally

Transcriptionally is an adverb relating to transcription, the process by which genetic information encoded in DNA is copied into RNA. It is used to describe how genes are transcribed or how a particular genomic region participates in transcription. In standard usage, transcriptional functions as the corresponding adjective (as in transcriptional regulation), while transcriptionally modifies verbs or phrases (for example, “transcriptionally active” or “transcriptionally silent” states).

In genomic and molecular biology, transcriptionally active regions are those where RNA synthesis occurs, whereas transcriptionally silent regions lack detectable transcription. Researchers assess transcriptional activity using methods such as RNA sequencing (RNA-seq) to measure RNA abundance, and techniques that directly monitor nascent transcription, like GRO-seq or PRO-seq. Transcriptional regulation involves promoters and core promoter elements, enhancers, transcription factors, and epigenetic features such as histone modifications and DNA methylation, which influence whether a gene is transcribed at a given time or in a particular cell type. Transcriptional control is distinct from post-transcriptional processes including RNA splicing, editing, transport, and degradation, which affect RNA after it is produced.

Usage notes: while transcriptional is the common adjective, transcriptionally often appears in descriptions of activity or state (for example, transcriptionally active loci). In most contexts, the meaning is clear from surrounding language; the term does not specify the mechanism of transcription, which may be explored by functional assays or sequencing-based approaches.