A lambda gt11 cDNA library from 10-day-old chicken embryo was screened immunologically using an antiserum against drebrins E1, E2 and A, proteins previously designated S5, S6 and S54, respectively. A cDNA clone for a common domain of drebrin was isolated. Northern blot analysis of chicken brain indicated that drebrin mRNAs are about 2.7 kilobases in molecular size and that expression of these proteins is developmentally regulated.