title: Expression profiling of repetitive elements by melting temperature analysis: variation in HERV-W gag expression across human individuals and tissues.
abstract: BACKGROUND
  Human endogenous retroviruses (HERV) constitute approximately 8% of the human genome and have long been considered "junk". The sheer number and repetitive nature of these elements make studies of their expression methodologically challenging. Hence, little is known of transcription of genomic regions harboring such elements.
  
  
  RESULTS
  Applying a recently developed technique for obtaining high resolution melting temperature data, we examined the frequency distributions of HERV-W gag element into 13 Tm categories in human tissues. Transcripts containing HERV-W gag sequences were expressed in non-random patterns with extensive variations in the expression between both tissues, including different brain regions, and individuals. Furthermore, the patterns of such transcripts varied more between individuals in brain regions than other tissues.
  
  
  CONCLUSIONS
  Thus, regulated expression of non-coding regions of the human genome appears to include the HERV-W family of repetitive elements. Although it remains to be established whether such expression patterns represent leakage from transcription of functional regions or specific transcription, the current approach proves itself useful for studying detailed expression patterns of repetitive regions.
authors.affiliation: Department of Neuroscience, Karolinska Institutet, Retzius Väg 8 B2:5, 17177 Stockholm, Sweden. christoffer.nellaker@gmail.com
authors.forename: Christoffer
authors.initials: C
authors.lastname: Nellåker
authors.forename: Fang
authors.initials: F
authors.lastname: Li
authors.forename: Fredrik
authors.initials: F
authors.lastname: Uhrzander
authors.forename: Joanna
authors.initials: J
authors.lastname: Tyrcha
authors.forename: Håkan
authors.initials: H
authors.lastname: Karlsson
mesh_terms: D020077:Endogenous Retroviruses / Q000235:genetics*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D015683:Gene Products, gag / Q000235:genetics*; D006801:Humans; D009691:Nucleic Acid Denaturation; D009928:Organ Specificity / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012091:Repetitive Sequences, Nucleic Acid; D044366:Transition Temperature
chemical_list: D015683:Gene Products, gag; D012333:RNA, Messenger