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Comparative
Reverse Transcription-Polymerase Chain Reaction and In Situ Hybridization
Analyses of Human Imprinted p57KIP2 and Insulin-Like Growth Factor 2 Gene
Transcripts in Fetal Kidney and Wilms' Tumors Using Archival Tissue |
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Hidenobu Soejima,
Janet McLay, Izuho Hatada, Tsunehiro Mukai, Yoshihiro Jinno, Norio Niikawa,
and Kankatsu Yun |
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Department
of Pathology (HS, JM, KY), Dunedin School of Medicine, University of Otago,
Dunedin, New Zealand; National Cardiovascular Center Research Institute
(IH, TM), Osaka, Japan; and Department of Human Genetics (YJ, NN), Nagasaki
University School of Medicine, Nagasaki, Japan |
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p57KIP2 (KIP2) is a cyclin-dependent
kinase inhibitor that arrests cells in G1 and an imprinted gene mapped on
chromosome 11p15.5. To investigate the role of KIP2 in Wilms' tumor (WT),
DNA and RNA were extracted from archival tissue sections of WT. KIP2 expression
was investigated by reverse transcription-polymerase chain reaction and
in situ mRNA hybridization. Thirteen of 39 WT were informative for length
polymorphism of KIP2 and subjected to reverse transcription-polymerase chain
reaction. KIP2 was expressed predominantly from one allele, although a low
level of expression was also detected from the other. Three WT with loss
of heterozygosity at the KIP2 locus demonstrated that the remaining KIP2
allele was still active, which was also confirmed by in situ hybridization.
Furthermore, among 13 KIP2-informative WT, 2 were heterozygous for insulin-like
growth factor II (IGF2). Allele-specific analysis demonstrated that one
showed monoallelic IGF2 expression, whereas the other showed biallelic expression.
In situ hybridization of fetal kidney showed that KIP2 transcripts were
detected in a variety of cell types, among which differentiated epithelial
structures showed higher expression than undifferentiated mesenchyme, whereas
IGF2 was expressed predominantly in undifferentiated mesenchyme and renal
vesicles of an early phase. WT demonstrated KIP2 and IGF2 hybridization
patterns similar to fetal kidney in that KIP2 transcripts were detected
in epithelial structures and blastema, whereas IGF2 transcripts were seen
in blastema and immature epithelial structures. Hybridization results indicated
that KIP2 expression in WT did not appear to be significantly reduced compared
with that in fetal kidney and that WT demonstrated a significant amount
of KIP2 transcripts regardless of retention or loss of heterozygosity at
the KIP2 locus. These data suggest that although KIP2 may play a role in
differentiation of the fetal kidney, it is not likely as a tumor suppressor
gene, which is implicated as the cause of the developmet of a majority of
WT. |
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