title: Identifier sequences are transcribed specifically in brain.
abstract: 'Identifier' or ID sequences are present in 62% of the RNA polymerase II and III transcripts made in vitro from brain nuclei but in fewer than 4% of the transcripts made from the nuclei of other tissues. An homologous 160-nucleotide cytoplasmic poly(A)+ RNA species, BC1, and a smaller species, BC2, are located in vivo exclusively in neural tissues. Cloned ID sequences are polymerase III templates in vitro. Our data suggest a model in which brain-specific polymerase III transcription of ID sequences located in introns of brain genes activates those genes in a primary manner for polymerase III transcription.
mesh_terms: D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000502:physiology*; D005786:Gene Expression Regulation; D009876:Operon; D012313:RNA / Q000235:genetics*; D012319:RNA Polymerase II / Q000235:genetics; D012320:RNA Polymerase III / Q000235:genetics; D051381:Rats; D014158:Transcription, Genetic
chemical_list: D012313:RNA; D012319:RNA Polymerase II; D012320:RNA Polymerase III