Tight junction protein ZO-2 is differentially expressed in normal pancreatic ducts compared to human pancreatic adenocarcinoma.
Differential display of hamster mRNA identified a fragment present in normal pancreatic duct cells that is not expressed in pancreatic duct carcinoma cells. Sequence analysis showed an 88% and 82% identity, respectively, to the cDNA of the canine and human tight junction zo-2 gene. Semi-quantitative RT-PCR analysis of human ZO-2 revealed a striking difference in the expression of various regions of the ZO-2 transcript in normal and neoplastic cells and the presence of an abnormality at the 5'-end of mRNA. RACE analysis identified 2 human ZO-2 mRNAs that encode proteins of different lengths, designated as ZO-2A and ZO-2C. The difference between the 2 forms of ZO-2 is the absence of 23 amino acid residues at the N terminus of ZO-2C compared with ZO-2A. Although ZO-2C was expressed in normal pancreatic cells and a majority of neoplastic tissues analyzed, ZO-2A was undetectable except in one case in all of the pancreatic adenocarcinomas analyzed. This suggests the presence of a yet to be identified motif important for cell-growth regulation within the 23-amino acid residue N-terminal peptide of ZO-2A, MPVRGDRGFPPRRELSGWLRAPG.
Chlenski
A
A
Department of Pathology and the Robert H. Lurie Cancer Center, Northwestern University Medical School, Chicago, IL 60611, USA.
Ketels
K V
KV
Tsao
M S
MS
Talamonti
M S
MS
Anderson
M R
MR
Oyasu
R
R
Scarpelli
D G
DG
D000230:Adenocarcinoma / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D015153:Blotting, Western; D006224:Cricetinae; D006801:Humans; D007150:Immunohistochemistry; D008565:Membrane Proteins / Q000032:analysis / Q000235:genetics*; D008969:Molecular Sequence Data; D010183:Pancreatic Ducts / Q000378:metabolism*; D010190:Pancreatic Neoplasms / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D062827:Zonula Occludens-2 Protein
D008565:Membrane Proteins; D012333:RNA, Messenger; C569046:TJP2 protein, human; D062827:Zonula Occludens-2 Protein