The gene encoding VEGFR2, the main receptor that binds and is activated by VEGF-A, is transcribed in almost every tissue type, but the VEGFR2 protein is rarely present. List and describe one mechanism that cells could use to reduce VEGFR2 protein levels despite high levels of transcription.

The RNA interference (RNAi) mechanism

Explanation:

RNA interference (RNAi) is a biological process by which endogenous non-coding RNAs (ncRNAs) sequences target messenger RNAs in order to inhibit gene expression and translation. The regulatory ncRNAs bind by complementary base pairing to specific mRNAs and thus promote gene silencing by both posttranscriptional (mRNA degradation, block translation, etc) and by transcriptional (recruiting of histone/DNA modifying enzymes) pathways. The most common types of evolutionarily conserved ncRNAs found in plant and animal cells are 1-small interfering RNAs (siRNAs), 2-microRNAs (miRNAs), 3-piwi interacting RNAs (piRNAs, only present in animal cells) and 4-long noncoding RNAs (lncRNAs).