Transcript regulation and carboxyterminal extension of ubiquitin in Dictyostelium discoideum

The sequence of a cDNA from Dictyostelium discoideum indicates linkage of a basic polypeptide to the C‐terminal end of ubiquitin. Among the six RNA species recognized by a ubiquitin‐specific fragment of the cDNA, four are increasing in quantity during development and two are decreasing. Six genomic Eco R1 fragments of more than 3 kb are recognized by that probe, suggesting that the RNAs are transcribed from a family of separate genes. A fragment containing only the 3'‐portion of the cDNA which includes part of the coding region for the basic polypeptide but not for ubiquitin, recognizes mainly two genomic fragments of which only one coincides in size with a fragment that is recognized by the ubiquitin‐specific probe.