The Cauliflower Mosaic Virus 35 <i>S</i> Promoter: Combinatorial Regulation of Transcription in Plants

TLDR

Transcription in higher plants depends on specific cis elements and their trans‑acting proteins, and the CaMV 35S promoter—known for driving constitutive expression—has been instrumental in elucidating these regulatory mechanisms. The promoter is modular, with subdomains that can drive tissue‑specific expression when dissected. Combining selected subdomains produces expression not seen in isolation, indicating synergistic cis‑element interactions, and the resulting expression patterns vary between tobacco and petunia, suggesting species‑specific interpretation of the combinatorial code.

Abstract

Appropriate regulation of transcription in higher plants requires specific cis elements in the regulatory regions of genes and their corresponding trans-acting proteins. Analysis of the cauliflower mosaic virus (CaMV) 35S promoter has contributed to the understanding of transcriptional regulatory mechanisms. The intact 35S promoter confers constitutive expression upon heterologous genes in most plants. Dissection into subdomains that are able to confer tissue-specific gene expression has demonstrated that the promoter has a modular organization. When selected subdomains are combined, they confer expression not detected from the isolated subdomains, suggesting that synergistic interactions occur among cis elements. The expression patterns conferred by specific combinations of 35S subdomains differ in tobacco and petunia. This indicates that a combinatorial code of cisregulatory elements may be interpreted differently in different species.