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Published on: January 22, 2013
Tissue-specific expression of novel messenger ribonucleic acids cloned from a renin-expressing kidney tumor cell line
H A Thompson1, J M Burson, J A Lang
1Department of Internal Medicine, University of Iowa College of Medicine, Iowa City 5224, USA.
Abstract:
As4.1 cells are derived from a renin-expressing kidney tumor induced by tissue-specific oncogene-mediated tumorigenesis in transgenic mice. These cells express high levels of renin messenger RNA (mRNA) and synthesize prorenin and renin; they were therefore used as a model to further investigate the molecular biology of renin-producing kidney cells by cloning and characterizing novel mRNAs expressed in these cells. One clone, designated 1.5, was randomly selected from an As4.1 complementary DNA (cDNA) library, and two other cDNA clones, designated 4.9 and 6.9, were obtained by screening the cDNA library using a strategy to identify As4.1 cell-specific mRNAs. Each clone exhibited a highly restricted tissue-specific expression profile, including high level expression in As4.1 cells and low level expression in kidney. No homology was found between the sequence of the partial 1.5 and 4.9 cDNAs and sequences in Genbank. Southern blot analysis revealed that clone 4.9 is encoded by a single copy gene containing at least two separate exons. A homology search of the sequence of clone 6.9 revealed it to encode a cDNA to serum amyloid A protein; consistent with this identification, expression of 6.9 mRNA was highly induced in both kidney and liver after treatment of mice with Escherichia coli lipopolysaccharide.
Insights
Researchers identified novel messenger RNAs (mRNAs) in renin-producing kidney tumor cells. These findings advance understanding of kidney cell molecular biology and potential diagnostic markers.
Area of Science:
- Molecular Biology
- Genetics
- Oncology
Background:
- As4.1 cells, derived from a renin-expressing kidney tumor in transgenic mice, serve as a model for studying renin-producing kidney cells.
- These cells exhibit high levels of renin messenger RNA (mRNA) and synthesize prorenin and renin.
Purpose of the Study:
- To investigate the molecular biology of renin-producing kidney cells.
- To clone and characterize novel mRNAs expressed in As4.1 cells.
Main Methods:
- Construction and screening of a complementary DNA (cDNA) library from As4.1 cells.
- Random selection and targeted screening of cDNA clones (1.5, 4.9, and 6.9).
- Sequence homology searches (GenBank) and Southern blot analysis for clone 4.9; homology search for clone 6.9.
Main Results:
- Three novel cDNA clones (1.5, 4.9, and 6.9) were identified with highly restricted tissue-specific expression, predominantly in As4.1 cells and at lower levels in kidney.
- Clones 1.5 and 4.9 showed no homology to existing GenBank sequences.
- Clone 4.9 is encoded by a single-copy gene with at least two exons.
- Clone 6.9 was identified as a cDNA to serum amyloid A protein, with its mRNA expression significantly induced in kidney and liver post-lipopolysaccharide treatment.
Conclusions:
- Novel mRNAs have been identified in renin-producing kidney tumor cells, contributing to the understanding of kidney cell molecular biology.
- The identified clones represent potential markers for kidney-specific gene expression.
- Clone 6.9 provides insights into the inflammatory response in kidney and liver tissues.
