|  |  | 
 
  |  | Ctbp2 should also be
  considered a high priority biological candidate gene responsible for
  modulating App expression levels. The C-terminal binding protein 2 is a
  transcriptional co-repressor also known as Ribeye. The gene produces two transcripts encoding distinct
  proteins. The short form is a transcriptional repressor that binds a
  Pro-X-Asp-Leu-Ser peptide motif and interacts with several transcription
  factors including EVI1, ZFPM1, and ZFHX1A (aka TCF8, deltaEF1). The longer
  isoform is a major component of specialized synapses in photoreceptors. Both
  proteins contain a NAD+ binding domain similar to NAD+-dependent
  2-hydroxyacid dehydrogenases. 
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  |  | 
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  |  | Notes: 
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  |  | 1. To find out more about
  CTBP2 protein and the Ctbp2 gene, link to iHOP at
  http://www.pdg.cnb.uam.es/UniPub/iHOP/ and type in CTBP2 
 | 
 
  |  | Try Arrowsmith at
  http://arrowsmith.psych.uic.edu/cgi-test/arrowsmith_uic/pubsmith.cgi 
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  |  | 2. Both APP and CTBP2 are
  involved in oxidoreducatase activity or Notch signaling. To establish this
  common gene ontology visit NCBI 
  http://www.ncbi.nih.gov/entrez/query.fcgi?db=gene and enter each gene
  symbol. 
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  |  | 3. You can get interesting
  hints regarding Ctbp2 expression partners by examining the genetic
  correlations between Ctbp2 probe set 1422887_a_at and all other transcripts
  on the M430 Affymetrix array. Use the Striatum data set because we already
  know from previous work (the previous slide) that this gene is a cis
  QTL.  You should be able to show
  that Ctbp2 and Notch3 have antagonistic expression patterns in striatum. The
  negative genetic correlation with E2f4 is even stronger. The transcript also
  has a high positive genetic correlation with Rdh14. Of particular interest
  with respect to APP protein processing, Ctbp2 covaries positively with Bace2
  (the transcript of the beta site APP-cleaving enzyme 2). 
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