Structure and Regulated Transcription of DIRS-1: An Apparent Retrotransposon of Dictyostelium discoideum

Abstract

Transposon- and retrovirus-like DNA segments form a major part of the repetitive DNA in many eukaryotes. They are a cause of many “spontaneous” mutations in Drosophila and other organisms, and many catalyze the rearrangements of large segments of DNA that have occurred during evolution (Flavell et al. 1981; Kleckner 1981; Spradling and Rubin 1981; Fedoroff 1983; Roeder and Fink 1983). In the course of cloning segments of Dictyostelium discoideum genomic DNA that are expressed preferentially during early differentiation, we isolated the DIRS-1 transposon (Zuker and Lodish 1981; Chung et al. 1983). DIRS-1 is unusual in that its transcription is induced either by heat shock or by the high cell density obtained during the early stages of differentiation. It is also novel in that its structure is unlike the structure of any transposon in prokaryotes or eukaryotes identified to date. DIRS-1 has been independently isolated by Rosen et al. (1983) who...