The tubulin gene cluster of Trypanosoma brucei starts with an intact beta-gene and ends with a truncated beta-gene interrupted by a retrotransposon-like sequence.

In Trypanosoma brucei the genes coding for alpha- and beta-tubulin are arranged in a single cluster comprising about ten alternating alpha and beta genes. The cluster starts at its 5' end with an intact beta gene. In this area, a 1.1-kb segment upstream of the mini-exon addition site has been sequenced. Several potential transcription signals were seen. The 3' end of the cluster terminates in the middle of a beta gene, making it an inactive truncated pseudogene. The adjoining 1.7-kb sequence shows a high degree of similarity with a retrotransposon-like (RTnL) element previously characterized elsewhere in the trypanosome genome. This is the first report of an RTnL element interrupting a protein-coding gene of T. brucei.