title: YY1 is autoregulated through its own DNA-binding sites.
abstract: BACKGROUND
  The transcription factor Yin Yang 1 (YY1) is a ubiquitously expressed, multifunctional protein that controls a large number of genes and biological processes in vertebrates. As a general transcription factor, the proper levels of YY1 protein need to be maintained for the normal function of cells and organisms. However, the mechanism for the YY1 homeostasis is currently unknown.
  
  
  RESULTS
  The current study reports that the YY1 gene locus of all vertebrates contains a cluster of its own DNA-binding sites within the 1st intron. The intact structure of these DNA-binding sites is absolutely necessary for transcriptional activity of the YY1 promoter. In an inducible cell line system that over-expresses an exogenous YY1 gene, the overall increased levels of YY1 protein caused a reduction in transcription levels of the endogenous YY1 gene. Reversion to the normal levels of YY1 protein restored the transcriptional levels of the endogenous YY1 to normal levels. This homeostatic response was also mediated through its cluster of YY1 binding sites.
  
  
  CONCLUSIONS
  Taken together, the transcriptional level of YY1 is self-regulated through its internal DNA-binding sites. This study identifies YY1 as the first known autoregulating transcription factor in mammalian genomes.
authors.affiliation: Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA. jeongkim@lsu.edu
authors.forename: Jeong Do
authors.initials: JD
authors.lastname: Kim
authors.forename: Sungryul
authors.initials: S
authors.lastname: Yu
authors.forename: Joomyeong
authors.initials: J
authors.lastname: Kim
mesh_terms: D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002460:Cell Line; D019143:Evolution, Molecular; D006706:Homeostasis; D006801:Humans; D007438:Introns; D051379:Mice; D008969:Molecular Sequence Data; D011485:Protein Binding; D015533:Transcriptional Activation; D050986:YY1 Transcription Factor / Q000235:genetics* / Q000378:metabolism*
chemical_list: D050986:YY1 Transcription Factor