Expression of the SmB' splicing protein in rodent cells capable of following an alternative RNA splicing pathway.

The expression of the SmB and SmB' spliceosome proteins in a variety of cell types and tissues has been investigated. Although SmB is found in all cells studied, the SmB' protein is found only in a small number of rodent cell types. The presence of this protein is correlated with the ability to utilize an alternative pathway of RNA splicing which is not available in most cell types. This is the first demonstration of tissue specific expression of a protein component of the spliceo-some and suggests a role for SmB' in the regulation of some cases of alternative RNA splicing.