Altering a histone H3K4 methylation pathway in glomerular podocytes promotes a chronic disease phenotype.
Methylation of specific lysine residues in core histone proteins is essential for embryonic development and can impart active and inactive epigenetic marks on chromatin domains. The ubiquitous nuclear protein PTIP is encoded by the Paxip1 gene and is an essential component of a histone H3 lysine 4 (H3K4) methyltransferase complex conserved in metazoans. In order to determine if PTIP and its associated complexes are necessary for maintaining stable gene expression patterns in a terminally differentiated, non-dividing cell, we conditionally deleted PTIP in glomerular podocytes in mice. Renal development and function were not impaired in young mice. However, older animals progressively exhibited proteinuria and podocyte ultra structural defects similar to chronic glomerular disease. Loss of PTIP resulted in subtle changes in gene expression patterns prior to the onset of a renal disease phenotype. Chromatin immunoprecipitation showed a loss of PTIP binding and lower H3K4 methylation at the Ntrk3 (neurotrophic tyrosine kinase receptor, type 3) locus, whose expression was significantly reduced and whose function may be essential for podocyte foot process patterning. These data demonstrate that alterations or mutations in an epigenetic regulatory pathway can alter the phenotypes of differentiated cells and lead to a chronic disease state.
Department of Pathology, University of Michigan, Ann Arbor, Michigan, United States of America.
Gaelle M
GM
Lefevre
Sanjeevkumar R
SR
Patel
Doyeob
D
Kim
Lino
L
Tessarollo
Gregory R
GR
Dressler
D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D002908:Chronic Disease; D004268:DNA-Binding Proteins; D005260:Female; D020869:Gene Expression Profiling; D006657:Histones / Q000378:metabolism*; D007668:Kidney / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure; D007674:Kidney Diseases / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D007678:Kidney Glomerulus / Q000166:cytology / Q000378:metabolism; D008239:Lysine / Q000378:metabolism; D008297:Male; D008745:Methylation; D051379:Mice; D018345:Mice, Knockout; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D008856:Microscopy, Fluorescence; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D050199:Podocytes / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure; D020812:Receptor, trkC / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction
D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D006657:Histones; D009687:Nuclear Proteins; C412792:Paxip1 protein, mouse; D020812:Receptor, trkC; D008239:Lysine