RNA Pol II Promotes Transcription of Centromeric Satellite DNA in Beetles

Pezer, Željka; Ugarković, Đurđica (2008) RNA Pol II Promotes Transcription of Centromeric Satellite DNA in Beetles. PLoS ONE, 3 (2). e1594-1-e1594-10. ISSN 1932-6203

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Abstract

Transcripts of centromeric satellite DNAs are known to play a role in heterochromatin formation as well as in establishment of the kinetochore. However, little is known about basic mechanisms of satellite DNA expression within constitutive heterochromatin and its regulation. Here we present comprehensive analysis of transcription of abundant centromeric satellite DNA, PRAT from beetle Palorus ratzeburgii (Coleoptera). This satellite is characterized by preservation and extreme sequence conservation among evolutionarily distant insect species. PRAT is expressed in all three developmental stages: larvae, pupae and adults at similar level. Transcripts are abundant comprising 0.033% of total RNA and are heterogeneous in size ranging from 0.5 kb up to more than 5 kb. Transcription proceeds from both strands but with 10 fold different expression intensity and transcripts are not processed into siRNAs. Most of the transcripts (80%) are not polyadenylated and remain in the nucleus while a small portion is exported to the cytoplasm. Multiple, irregularly distributed transcription initiation sites as well as termination sites have been mapped within the PRAT sequence using primer extension and RLM-RACE. The presence of cap structure as well as poly(A) tails in a portion of the transcripts indicate RNA polymerase II – dependent transcription and a putative polymerase II promoter site overlaps the most conserved part of the PRAT sequence. The treatment of larvae with alpha-amanitin decreases the level of PRAT transcripts at concentrations that selectively inhibit pol II activity. In conclusion, stable, RNA polymerase II dependant transcripts of abundant centromeric satellite DNA, not regulated by RNAi, have been identified and characterized. This study offers a basic understanding of expression of highly abundant heterochromatic DNA which in beetle species constitutes up to 50% of the genome.

Item Type:	Article
Uncontrolled Keywords:	heterochromatin; centromere; non-coding RNA; satellite DNA; transcription; Coleoptera
Subjects:	NATURAL SCIENCES > Biology
Divisions:	Division of Molecular Biology
Projects:	Project title Project leader Project code Project type Evolucija i funkcija brzo evoluirajućeg dijela eukariotskog genoma [3874] Đurđica Ugarković 098-0982913-2832 MZOS
Depositing User:	Đurđica Ugarković
Date Deposited:	02 Mar 2015 16:11
URI:	http://fulir.irb.hr/id/eprint/1697
DOI:	10.1371/journal.pone.0001594

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