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Cloning of mouse c-ros renal cDNA, its role in development and relationship to extracellular matrix glycoproteins
1Department of Pathology, Northwestern University Medical School, Chicago, Illinois, USA.
Abstract:
Renal organogenesis ensues following reciprocal interactions between the uninduced metanephric mesenchyme and the ureteric bud. Conceivably, the presence of ligands or growth factors on a given cell type, and expression of receptors, including receptor proto-oncogenes, on the other cell type of different lineage would facilitate such epithelial-mesenchymal interactions. During these interactions, other macromolecules, such as extracellular matrix (ECM) proteins, present at the epithelial-mesenchymal surface, also play a role in the kidney morphogenesis. In this study the proto-oncogene, c-ros, was cloned and sequenced; its role in the metanephric development was examined, and correlated with the changes in the expression of ECM proteins. The mouse c-ros renal cDNA, belonging to phosphotyrosine kinase (PTK) receptor family, had a translation product of 2340 amino acids. The extracellular domain had 32 N-linked glycosylation sites and 30 cysteine residues. The transmembrane segment had a hydrophobicity approaching approximately 3.5. Multiple phosphorylation sites, typical of a PTK catalytic unit, were present in the cytoplasmic domain. The 3' noncoding region did not contain any A(U)nA mRNA instability motifs. The c-ros mRNA was highly expressed on the ureteric bud branches and their tips and on the developing glomeruli. Competitive RT-PCR analyses revealed the c-ros expression was the highest at 13th day of gestation, and it declined to very low levels during the neonatal period. Exposure of metanephric kidneys to c-ros antisense-oligonucleotide, derived from the PTK domain, caused dysmorphogenesis of the kidney and loss of c-ros expression on the ureteric bud branches. Concomitant with the reduced c-ros gene expression, a decreased expression of ECM glycoproteins, in particular the proteoglycans, was observed. These findings suggest that the c-ros plays a role in the metanephric development, and its effects may be modulated by the ECM macromolecules present at the epithelial-mesenchymal interface.
Insights
The proto-oncogene c-ros is crucial for kidney development, influencing ureteric bud branching and glomeruli formation. Its expression impacts extracellular matrix proteins essential for kidney morphogenesis.
Area of Science:
- Developmental Biology
- Molecular Biology
- Genetics
Background:
- Renal organogenesis involves complex reciprocal interactions between the metanephric mesenchyme and ureteric bud.
- Epithelial-mesenchymal interactions during kidney development are mediated by cell surface receptors and extracellular matrix (ECM) proteins.
- Proto-oncogenes, such as c-ros, are implicated in cellular signaling pathways that regulate development.
Purpose of the Study:
- To clone and sequence the mouse c-ros proto-oncogene and investigate its role in metanephric development.
- To correlate c-ros expression with changes in ECM protein expression during kidney organogenesis.
- To understand the functional significance of c-ros in kidney morphogenesis.
Main Methods:
- Cloning and sequencing of mouse c-ros renal cDNA.
- Analysis of c-ros mRNA expression patterns using RT-PCR.
- Functional assessment via exposure to c-ros antisense-oligonucleotide to disrupt gene expression.
- Evaluation of ECM protein expression changes.
Main Results:
- Mouse c-ros encodes a phosphotyrosine kinase (PTK) receptor with specific structural features.
- c-ros mRNA is highly expressed in the ureteric bud and developing glomeruli, peaking at day 13 of gestation.
- Inhibition of c-ros expression using antisense-oligonucleotide led to kidney dysmorphogenesis and reduced ureteric bud branching.
- Reduced c-ros expression correlated with decreased expression of ECM glycoproteins, particularly proteoglycans.
Conclusions:
- The proto-oncogene c-ros plays a significant role in metanephric development and kidney organogenesis.
- c-ros signaling appears to influence ureteric bud branching and glomerular development.
- The function of c-ros in kidney development may be modulated by interactions with ECM macromolecules.