Differential control of both cell cycle-regulated and quantitative histone mRNA expression by Drosophila Mute.

Drosophila Mute represses histone mRNA outside S phase and differentially promotes expression of specific histone genes during S phase.

• Why it matters: Proper regulation of histone gene expression is crucial for genome stability and development, but how histone genes are turned off after S phase remains unclear.
• What they did: The study used genetic and molecular approaches to show that Mute counteracts Cyclin E/Cdk2-dependent phosphorylation of Mxc, regulating histone mRNA levels, and promotes high expression of H1, H2a, and H2b during S phase.
• The result: Loss of Mute causes abnormal histone mRNA accumulation and leads to 801 differentially expressed genes, mainly related to muscle processes, resulting in developmental defects.