Transcriptional profiling of PRKG2-null growth plate identifies putative down-stream targets of PRKG2.
BACKGROUND
Kinase activity of cGMP-dependent, type II, protein kinase (PRKG2) is required for the proliferative to hypertrophic transition of growth plate chondrocytes during endochondral ossification. Loss of PRKG2 function in rodent and bovine models results in dwarfism. The objective of this study was to identify pathways regulated or impacted by PRKG2 loss of function that may be responsible for disproportionate dwarfism at the molecular level.


METHODS
Microarray technology was used to compare growth plate cartilage gene expression in dwarf versus unaffected Angus cattle to identify putative downstream targets of PRGK2.


RESULTS
Pathway enrichment of 1284 transcripts (nominal p < 0.05) was used to identify candidate pathways consistent with the molecular phenotype of disproportionate dwarfism. Analysis with the DAVID pathway suite identified differentially expressed genes that clustered in the MHC, cytochrome B, WNT, and Muc1 pathways. A second analysis with pathway studio software identified differentially expressed genes in a host of pathways (e.g. CREB1, P21, CTNNB1, EGFR, EP300, JUN, P53, RHOA, and SRC). As a proof of concept, we validated the differential expression of five genes regulated by P53, including CEBPA, BRCA1, BUB1, CD58, and VDR by real-time PCR (p < 0.05).


CONCLUSIONS
Known and novel targets of PRKG2 were identified as enriched pathways in this study. This study indicates that loss of PRKG2 function results in differential expression of P53 regulated genes as well as additional pathways consistent with increased proliferation and apoptosis in the growth plate due to achondroplastic dwarfism.
Department of Animal Science, Iowa State University, 2255 Kildee Hall, Ames, IA, 50011, USA. jekoltes@iastate.edu.
James E
JE
Koltes
National Bureau of Animal Genetic Resources, Karnal, 132001, Haryana, India. dineshkumarbhu@gmail.com.|Current address: Centre for Agricultural Bioinformatics, Indian Agricultural Statistics Research Institute, Library Avenue, PUSA, New Delhi, 110012, India. dineshkumarbhu@gmail.com.
Dinesh
D
Kumar
National Bureau of Animal Genetic Resources, Karnal, 132001, Haryana, India. katariaranji@yahoo.co.in.
Ranjit S
RS
Kataria
Veterinary Diagnostics and Production Animal Medicine, Iowa State University College of Veterinary Medicine, Ames, IA, 50011-3150, USA. vcooper@iastate.edu.
Vickie
V
Cooper
Department of Animal Science, Iowa State University, 2255 Kildee Hall, Ames, IA, 50011, USA. jreecy@iastate.edu.
James M
JM
Reecy
D000818:Animals; D017209:Apoptosis / Q000235:genetics; D002417:Cattle; D002453:Cell Cycle / Q000235:genetics; D062967:Cyclic GMP-Dependent Protein Kinase Type II / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D063990:Gene Ontology; D006132:Growth Plate / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D015203:Reproducibility of Results; D012984:Software; D014158:Transcription, Genetic; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
D016159:Tumor Suppressor Protein p53; D062967:Cyclic GMP-Dependent Protein Kinase Type II