PRAC: A novel small nuclear protein that is specifically expressed in human prostate and colon.
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.
Liu
X F
XF
Laboratory of Molecular Biology, Division of Basic Sciences, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA.
Olsson
P
P
Wolfgang
C D
CD
Bera
T K
TK
Duray
P
P
Lee
B
B
Pastan
I
I
D000595:Amino Acid Sequence; D000912:Antibodies, Neoplasm / Q000032:analysis / Q000096:biosynthesis; D001483:Base Sequence; D015152:Blotting, Northern; D015153:Blotting, Western; D002886:Chromosomes, Human, Pair 17; D003106:Colon / Q000378:metabolism / Q000502:physiology; D003110:Colonic Neoplasms / Q000235:genetics / Q000378:metabolism*; D020224:Expressed Sequence Tags; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000096:biosynthesis* / Q000235:genetics; D010957:Plasmids; D011467:Prostate / Q000378:metabolism / Q000502:physiology; D011471:Prostatic Neoplasms / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D019105:Random Amplified Polymorphic DNA Technique; D012007:Rectum / Q000378:metabolism / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured
D000912:Antibodies, Neoplasm; D009687:Nuclear Proteins; C425926:PRAC1 protein, human; D012333:RNA, Messenger