Identifying biological pathways that underlie primordial short stature using network analysis.

Abstract

Mutations in CUL7, OBSL1 and CCDC8, leading to disordered ubiquitination, cause one of the commonest primordial growth disorders, 3-M syndrome. This condition is associated with i) abnormal p53 function, ii) GH and/or IGF1 resistance, which may relate to failure to recycle signalling molecules, and iii) cellular IGF2 deficiency. However the exact molecular mechanisms that may link these abnormalities generating growth restriction remain undefined. In this study, we have used immunoprecipitation/mass spectrometry and transcriptomic studies to generate a 3-M 'interactome', to define key cellular pathways and biological functions associated with growth failure seen in 3-M. We identified 189 proteins which interacted with CUL7, OBSL1 and CCDC8, from which a network including 176 of these proteins was generated. To strengthen the association to 3-M syndrome, these proteins were compared with an inferred network generated from the genes that were differentially expressed in 3-M fibroblasts compared with controls. This resulted in a final 3-M network of 131 proteins, with the most significant biological pathway within the network being mRNA splicing/processing. We have shown using an exogenous insulin receptor (INSR) minigene system that alternative splicing of exon 11 is significantly changed in HEK293 cells with altered expression of CUL7, OBSL1 and CCDC8 and in 3-M fibroblasts. The net result is a reduction in the expression of the mitogenic INSR isoform in 3-M syndrome. From these preliminary data, we hypothesise that disordered ubiquitination could result in aberrant mRNA splicing in 3-M; however, further investigation is required to determine whether this contributes to growth failure.

• Authors: Dan Hanson, Adam Stevens, Philip G Murray, Graeme C M Black, Peter E Clayton
• Journal: Journal of molecular endocrinology (J Mol Endocrinol) Vol. 52 Issue 3 Pg. 333-44 (Jun 2014) ISSN: 1479-6813 [Electronic] England
• PMID: 24711643 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2014 The authors.

Chemical References

• Antigens, CD
• CCDC8 protein, human
• CUL7 protein, human
• Carrier Proteins
• Cullin Proteins
• Cytoskeletal Proteins
• IGF1 protein, human
• IGF2 protein, human
• OBSL1 protein, human
• Tumor Suppressor Protein p53
• Human Growth Hormone
• Insulin-Like Growth Factor I
• Insulin-Like Growth Factor II
• INSR protein, human
• Receptor, Insulin

Topics

• Alternative Splicing (genetics)
• Antigens, CD (genetics)
• Carrier Proteins (biosynthesis, genetics)
• Cell Line, Tumor
• Cullin Proteins (biosynthesis, genetics)
• Cytoskeletal Proteins (biosynthesis, genetics)
• Dwarfism (genetics)
• Fibroblasts
• Gene Expression Profiling
• Growth Disorders (genetics)
• HEK293 Cells
• Human Growth Hormone (genetics)
• Humans
• Insulin-Like Growth Factor I (genetics)
• Insulin-Like Growth Factor II (deficiency, genetics)
• Muscle Hypotonia (genetics)
• Receptor, Insulin (genetics)
• Spine (abnormalities)
• Tumor Suppressor Protein p53 (genetics)
• Ubiquitination (genetics)