Dataset Information

PCR-based detection of Pol III-transcribed transposons and its application to the rodent model of ultraviolet response.

ABSTRACT: Cellular levels of RNAs containing transposable elements increase in response to various stresses. Polymerase III (Pol III)-dependent transcripts of transposons are different from transposon-containing RNAs generated by read-through Pol II-dependent transcription. Until now, Pol III transcripts were detected by primer extension followed by time-consuming gel electrophoresis. In this paper, we describe a more sensitive PCR-based method for the selective detection of Pol III-transcribed RNAs. The method is based on the difference in sequences at the 5' ends of the Pol II- and Pol III-dependent transcripts. We employed this method to quantify Pol III transcripts of transposon B1 in rodent cells and revealed that their levels are affected by UV irradiation. We therefore conclude that the abundance of the Pol III-transcribed fraction of cellular RNA may serve as marker of stress response and can be conveniently quantified by the method described.

SUBMITTER: Myakishev M

PROVIDER: S-EPMC2666214 | biostudies-other | 2008

REPOSITORIES: biostudies-other

ACCESS DATA

Similar Datasets

Project description:BACKGROUND: Mobile genetic elements comprise a substantial fraction of vertebrate genomes. These genes are considered to be deleterious, and in vertebrates they are usually inactive. High throughput sequencing of salmonid fish cDNA libraries has revealed a large number of transposons, which remain transcribed despite inactivation of translation. This article reports on the structure and potential role of these genes. RESULTS: A search of EST showed the ratio of transcribed transposons in salmonid fish (i.e., 0.5% of all unique cDNA sequences) to be 2.4-32 times greater than in other vertebrate species, and 68% of these genes belonged to the Tc1-family of DNA transposons. A phylogenetic analysis of reading frames indicate repeated transposition of distantly related genes into the fish genome over protracted intervals of evolutionary time. Several copies of two new DNA transposons were cloned. These copies showed relatively little divergence (11.4% and 1.9%). The latter gene was transcribed at a high level in rainbow trout tissues, and was present in genomes of many phylogenetically remote fish species. A comparison of synonymous and non-synonymous divergence revealed remnants of divergent evolution in the younger gene, while the older gene evolved in a neutral mode. From a 1.2 MB fragment of genomic DNA, the salmonid genome contains approximately 10(5) Tc1-like sequences, the major fraction of which is not transcribed. Our microarray studies showed that transcription of rainbow trout transposons is activated by external stimuli, such as toxicity, stress and bacterial antigens. The expression profiles of Tc1-like transposons gave a strong correlation (r2 = 0.63-0.88) with a group of genes implicated in defense response, signal transduction and regulation of transcription. CONCLUSION: Salmonid genomes contain a large quantity of transcribed mobile genetic elements. Divergent or neutral evolution within genomes and lateral transmission can account for the diversity and sustained persistence of Tc1-like transposons in lower vertebrates. A small part of transposons remain transcribed and their transcription is enhanced by responses to acute conditions.

Dataset Information

PCR-based detection of Pol III-transcribed transposons and its application to the rodent model of ultraviolet response.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets