Characterization of the chicken transitin gene reveals a strong relationship to the nestin intermediate filament class

Our laboratory previously reported that transitin is a radial glial interme diate filament protein sharing the basic structural features common to all intermediate filament (IF) proteins. It contains an a-helical core domain f lanked by a short nonhelical head and a long COOH-terminal tail. The core s equence of transitin shows the greatest similarity to Xenopus tanabin and t o rat and human nestin. We also reported that transitin has multiple splice variants derived from the deletion or inclusion of a leucine-zipper heptad repeat domain in the COOH-terminal tail. In the present study, we provide new evidence to support the classification of nestin and transitin in the s ame group of IF proteins based on the number and position of its introns. I n addition, we suggest that the different isoforms of transitin are produce d by a splicing mechanism that recognizes consensus 5' and 3' splice sites contained within the coding sequence of the leucine-zipper heptad repeat do main.