The ability of certain antibiotics to persuade the ribosome to "read-through" nonsense mutations and lead to expression of functional proteins, was discovered over 30 years ago. We have designed a novel screening vector for identifying new read-through agents. Using this vector we have isolated new antibiotic families that exhibited significant read-through abilities. We find that macrolides can restore the function of mutated proteins in different diseases (A-T, SMA and RETT syndrome), and especially in colorectal cancer which result from mutations in the APC gene.