How can I determine if a protein has been knocked out?

To determine is a protein has been knocked out, one of the best options is to conduct a western blot (also known as an immunoblot). By employing an antibody specific for the protein of interest, a western blot can allow you to compare the knockout clone with the wild-type and determine if a protein has been successful knocked out. Another method for screening if a knockout is successful is RT-qPCR, which can allow you to analyze gene expression.