SALL4 mediates teratogenicity as a thalidomide-dependent cereblon substrate

Area of Science:

• Biochemistry
• Genetics
• Pharmacology

Background:

• Cereblon (CRBN) is a key protein in targeted protein degradation, offering therapeutic potential.
• Thalidomide, a CRBN-binding drug, is associated with severe birth defects (phocomelia).
• Understanding CRBN-mediated teratogenicity is crucial for developing safer therapeutics.

Purpose of the Study:

• To investigate the mechanism underlying thalidomide's teratogenicity.
• To identify the specific molecular targets of thalidomide responsible for birth defects.
• To explore the potential for developing safer CRBN-modulating therapeutics.

Main Methods:

• Utilized transgenic mice expressing human cereblon to assess teratogenicity.
• Identified novel cereblon neosubstrates using biochemical and genetic approaches.
• Analyzed SALL4 protein sequence variations in different species to explain differential sensitivity.

Main Results:

• Thalidomide was not teratogenic in transgenic mice expressing human cereblon.
• Identified SALL4 as a thalidomide-dependent cereblon neosubstrate.
• SALL4 mutations cause syndromes overlapping with thalidomide embryopathy; SALL4 degradation varies by species due to sequence differences.

Conclusions:

• Cereblon binding alone does not cause thalidomide's teratogenicity; SALL4 is a critical mediator.
• This study expands the understanding of cereblon neosubstrates to include C2H2 zinc finger proteins.
• Elucidating the molecular basis of thalidomide teratogenicity provides a pathway for safer drug development.