PRAC: A novel small nuclear protein that is specifically expressed in human prostate and colon

Prostate. 2001 May 1;47(2):125-31. doi: 10.1002/pros.1055.


Background: The database of human Expressed Sequence Tags (dbEST) provides a potential source for identification of tissue-specific genes. This database contains sequences that originate from cDNA libraries from particular tumors, organs or cell types. In this report, we have used the EST database to identify PRAC, a novel gene specifically expressed in human Prostate, prostate cancer, Rectum And distal Colon.

Methods: Using a computer based analysis, a cluster of sequence homologous ESTs was identified which contained ESTs derived only from human prostate cDNA libraries. The tissue specificity was examined by multiple tissue RNA dot blots and RT-PCR. The PRAC transcript and protein was identified using Northern blot analysis, RACE-PCR, primer extension, and western blot.

Results: PRAC encode a 382 nucleotide RNA found in prostate, rectum, distal colon, and in three prostate cancer cell lines; LNCaP, PC-3 and DU145. This transcript encodes a 6 kDa nuclear protein. The PRAC gene is located on chromosome 17 at position 17q21, about 4 kbp downstream from the homeodomain Hoxb-13 gene.

Conclusions: Our data proves that the EST database can be a useful tool for discovery of prostate-specific genes. The nuclear localization, identification of potential phosphorylation sites, and possible cotranscription with the Hoxb-13 gene suggest that PRAC may have a regulatory role in the nucleus.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Antibodies, Neoplasm / analysis
  • Antibodies, Neoplasm / biosynthesis
  • Base Sequence
  • Blotting, Northern
  • Blotting, Western
  • Chromosomes, Human, Pair 17
  • Colon / metabolism
  • Colon / physiology
  • Colonic Neoplasms / genetics
  • Colonic Neoplasms / metabolism*
  • Expressed Sequence Tags
  • Humans
  • Male
  • Molecular Sequence Data
  • Nuclear Proteins / biosynthesis*
  • Nuclear Proteins / genetics
  • Plasmids
  • Prostate / metabolism
  • Prostate / physiology
  • Prostatic Neoplasms / genetics
  • Prostatic Neoplasms / metabolism*
  • RNA, Messenger / biosynthesis
  • RNA, Messenger / genetics
  • Random Amplified Polymorphic DNA Technique
  • Rectum / metabolism
  • Rectum / physiology
  • Reverse Transcriptase Polymerase Chain Reaction
  • Tumor Cells, Cultured


  • Antibodies, Neoplasm
  • Nuclear Proteins
  • PRAC1 protein, human
  • RNA, Messenger