GEOapplication/xmlftp://ftp.ncbi.nlm.nih.gov/geo/series/GSE309nnn/GSE309306/primaryOK200TranscriptomicsMus musculusExpression profiling by high throughput sequencinghttps://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE309306GEOGSEfalseSubstantial Adaptability of Mononuclear Polyploid Cardiomyocytes Revealed by Perinatal Loss of Chaf1aHere, we show that chromatin assembly factor 1 subunit A (Chaf1a), a key regulator of nucleosome deposition during DNA replication, is essential for postnatal cardiomyocyte proliferation and binucleation. Using cardiomyocyte-specific Chaf1a knockout mice (Myh6-Cre; Chaf1af/f), we demonstrate that Chaf1a deficiency disrupts karyokinesis, leading to a marked increase in the proportion of mononuclear polyploid cardiomyocytes and a reduction in binucleated cells. This results in nearly 50% fewer cardiomyocytes, yet strikingly, the hearts preserve baseline function through substantial compensatory hypertrophy without significant fibrosis. Notably, following cardiac apex resection, neonatal Myh6-Cre; Chaf1af/f mice fail to regenerate myocardium, highlighting the essential role of Chaf1a in cardiac regeneration.2026/07/17GSE309306GSM9484096GSM9484095GSM9264589GSM9484098GSM9264588GSM9264587GSM9484097GSM9264586GSM9264591GSM9264590GSM9484100GSM948409924247309306Mus musculus