TRANSFER-RNA GENE OF XENOPUS-LAEVIS CONTAINS AT LEAST 2 SITES PROMOTING TRANSCRIPTION

A small cloned DNA segment previously shown to contain all genetic information for the expression of the tRNAmet gene of Xenopus laevis was cleaved into an anterior and posterior portion by Hae III restriction. Both restriction fragments were cloned in pCRL using EooRI linkers. Starting from these tDNA subclones, a series of new recombinants were constructed. The transcriptional activity of the cloned DNA's was tested both in an in vitro transcriptional system and by means of the oocyte injection technique. It was shown that both the 5′ and 3′ ends of the cloned gene unit were essential for transcription. We have developed a model for the functional organization of the tRNAmet gene. We propose that the gene contains a regulatory site situated near the 3′ portion of the gene unit. For transcription to occur both in vivo and in vitro a specific initiation site near the 5′ end of the gene is required. © 1979 Information Retrieval Limited.