title: Altered expression of PIWI RNA in the rat brain after transient focal ischemia.
abstract: OBJECTIVE
  The PIWI-interacting RNA (piRNA) is the most predominant RNA species in eukaryotes. The piRNA are a class of noncoding RNAs that bind and degrade the RNA formed by the transposons to control the transposon-induced gene mutations. The role of piRNA after focal ischemia is not yet evaluated.
  
  
  METHODS
  We profiled 39 727 piRNAs in the cerebral cortex of adult rats subjected to transient focal ischemia using microarrays. The RT targets of stroke-responsive piRNAs were identified with bioinformatics. To understand how piRNAs are controlled, we analyzed the transcription factor binding sites in the putative promoters of 10 representative stroke-responsive piRNAs.
  
  
  RESULTS
  In the ipsilateral cortex of ischemic rats, 105 piRNAs showed altered expression (54 up- and 51 downregulated; >2.5-fold) compared with shams. Twenty-five of those showed a >5-fold change. A bioinformatics search showed that the transposon targets of the highly stroke-responsive piRNAs are distributed among the 20 autosomal chromosomes and there is a redundancy in the targets between the piRNAs. Furthermore, the transposon targets were observed to be highly repetitious for each piRNA across the chromosome length. Of the 159 transcription factors observed to have binding sites in the piRNA gene promoters, 59% belonged to 20 major families indicating that transcription factors control stroke-responsive piRNAs in a redundant manner.
  
  
  CONCLUSIONS
  The present study is the first to show that many piRNAs are expressed in adult rodent brain and several of them respond to focal ischemia.
authors.affiliation: Department of Neurological Surgery, University of Wisconsin, 600 Highland Avenue, Madison, WI 53792, USA.
authors.forename: Ashutosh
authors.initials: A
authors.lastname: Dharap
authors.forename: Venkata Prasuja
authors.initials: VP
authors.lastname: Nakka
authors.forename: Raghu
authors.initials: R
authors.lastname: Vemuganti
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D015536:Down-Regulation / Q000235:genetics; D020869:Gene Expression Profiling / Q000379:methods; D005786:Gene Expression Regulation / Q000235:genetics*; D020244:Infarction, Middle Cerebral Artery / Q000235:genetics / Q000378:metabolism; D002546:Ischemic Attack, Transient / Q000235:genetics* / Q000378:metabolism; D008297:Male; D011401:Promoter Regions, Genetic; D011485:Protein Binding / Q000235:genetics; D034741:RNA, Small Interfering / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000235:genetics*; D022661:RNA, Untranslated / Q000235:genetics / Q000378:metabolism; D051381:Rats; D011918:Rats, Inbred SHR; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D015854:Up-Regulation / Q000235:genetics
chemical_list: D034741:RNA, Small Interfering; D022661:RNA, Untranslated; D014157:Transcription Factors