Tau is a microtubule-associated protein that plays a key role in the development of certain brain disorders. to analyze tau expression, mouse brain extracts are made at different developmental stages, separated on an sds-page gel, and analyzed by western blot with antibodies recognizing only mouse tau protein. if the results at the right represent tau’s normal expression pattern, the two different size protein products could result from:
1. transcription of tau dna in different directions.
2. translation of tau mrnas of different sizes.
3. expression of two different genes.
4. different chemical modifications of tau protein.