A Family of Target Site-Specific Retrotransposons Interrupts Spliced Leader RNA Genes in Trypanosomatids

Abstract

Retrotransposons are mobile genetic elements that have been found in almost every genome. Because they do not code for any coat protein sequences, it is believed that they have lost the ability to maintain an extracellular life cycle yet they share many other gene homologies with retroviral genomes. Their replication involves an RNA intermediate and the activity of the reverse-transcriptase enzyme for which they code. Although the majority of these elements are promiscuous in their insertion, there are a few examples that integrate into specific target sites. One such integration site-specific element interrupts the spliced leader RNA genes of organisms of several genera within the family Trypanosomatidae. These elements constitute a highly related family of sequences that most likely have evolved through a common ancestor.