The nuclear lamina constitutes more than a structural scaffold for the nucleus and plays a crucial role in protection of genomic integrity. Here we report that the loss of the lysine acetyl-transferase (KAT) MOF leads to nuclear architecture defects during interphase including micronuclei formation. We identify Lamin A/C, a major component of the nuclear lamina, to be an acetylation target of MOF. A point mutation in Lamin A phenocopies nuclear morphology defects observed upon Mof-deletion. Through single cell DNA sequencing, we reveal that either loss of Mof or Lamin A mutation result in extensive genomic instability, including chromothripsis. Our work establishes MOF-dependent Lamin acetylation as a key regulator of nuclear architecture maintenance in mammals.