Nucleic Acids Research, 1985, Vol. 13, No. 9 3389-3403
© 1985
Articles |
Transcriptional measurements of mouse repeated DNA sequences
Departments of Genetics and Microbiology and Immunology, Albert Einstein College of Medicine 1300 Morris Park Avenue, Bronx, NY 10461, USA
Received December 27, 1984. Revised April 5, 1985. Accepted April 5, 1985.
We have carried out transcriptional measurements on several families of repeated sequences to define their expression in mouse cells. The majority of Alu family transcripts result from read-through from adjacent structural gene promoters while 20% are discrete RNA polymerase III products. Alu repeat members show preferential orientation within RNA polymerase II transcription units as evidenced by asymmetric representation of the complementary strands of the Alu family in hnRNA. We assessed whether 3 non-Alu repeated sequence families had their own promoters by strand symmetry measurements and size distribution analysis of repeat-homologous newly synthesized nuclear RNA. Transcription homologous to the R family is totally symmetric and is likely due to read-through from adjacent structural gene promoters. LLRep1 and Bam5 repeats in contrast, exhibit consistent strand asymmetry which is suggestive that at least some members may be transcribed by their own promoters. Among 3 mouse tissues and 1 cultured cell line analyzed, no quantitative variation in the expression of any of these sequences was observed.
*Present address: Pediatric Genetics, Baylor College of Medicine, Houston, TX 77030, USA