CREBBP re-arrangements affect protein function and lead to aberrant neuronal differentiation

Area of Science:

• Neuroscience
• Molecular Biology
• Genetics

Background:

• Biallelic inactivation of CREB-binding protein (CREBBP) causes embryonic lethality in mice.
• Human CREBBP rearrangements are linked to Rubinstein-Taybi Syndrome (RSTS), characterized by craniofacial, skeletal, and neuronal defects.
• CREBBP is crucial for synaptic plasticity and long-term memory, suggesting its role in neuronal function.

Purpose of the Study:

• To investigate the role of CREBBP rearrangements in neuronal differentiation.
• To understand how CREBBP mutations affect key signaling pathways involved in neurogenesis.
• To explore the molecular mechanisms underlying neuronal defects in RSTS.

Main Methods:

• Generated deletion constructs of CREBBP (pDeltaCB-HAT, pDeltaHAT-CT) and transfected them into NT2 cells.
• Performed expression profiling of Notch, Wnt, SHH, and Retinoid signaling pathway components and neuronal markers.
• Utilized ChIP-PCR and co-immunoprecipitation to analyze CREBBP interactions and chromatin binding.

Main Results:

• CREBBP domain deletions (CB-HAT, HAT-CT) resulted in altered cell proliferation and differentiation phenotypes.
• Mutant cells exhibited changes in HAT activity, cell cycle profiles, and basal expression of critical signaling pathways.
• Aberrant CREBBP structure led to altered transcription factor binding affinities and aberrant gene transcription.

Conclusions:

• CREBBP rearrangements significantly impair neuronal differentiation at the genomic level.
• Altered CREBBP structure disrupts essential signaling pathways, leading to differentiation defects.
• These findings provide insights into the molecular basis of neuronal abnormalities in RSTS.