Which of the following steps is common to the processing of both miRNAs and siRNAs?

RNAi is currently being tested as a therapeutic tool for genetic diseases and other conditions. Consider the following: cystic fibrosis caused by loss of function of the CFTR gene, HIV infection, and cancer caused by hyperactivity of a growth factor receptor. Which of these may be treatable by RNAi, and which not? Explain your reasoning.

Explain how the expression of a single gene can be quickly, efficiently, and specifically shut down at the transcriptional, posttranscriptional, and posttranslational stages through the coordinated expression of a transcriptional repressor, an miRNA, and a ubiquitin ligase.

siRNAs target a variety of different RNA transcripts for degradation.