Assembly mechanism of Integrator's RNA cleavage module.

Area of Science:

• Molecular Biology
• Gene Regulation
• Biochemistry

Background:

• The Integrator complex is essential for embryonic development, regulating gene expression and RNA processing.
• Its endonuclease activity, crucial for these functions, resides in the INTS4-9-11 RNA cleavage module.
• The assembly mechanism of this critical module remained largely unknown.

Purpose of the Study:

• To elucidate the mechanism of Integrator cleavage module assembly in humans.
• To identify the factors involved in the biogenesis of the INTS4-9-11 module.
• To understand the role of BRAT1 and WDR73 in Integrator complex formation and function.

Main Methods:

• Investigated the roles of BRAT1 and WDR73 in the maturation of the Integrator cleavage module.
• Utilized biochemical assays to analyze protein interactions and complex assembly.
• Studied the impact of mutations and the role of inositol hexaphosphate (IP6) in module formation.

Main Results:

• BRAT1 and WDR73 act as critical biogenesis factors for the Integrator cleavage module.
• They prevent premature activity by blocking the endonuclease active site and INTS4 association.
• BRAT1 facilitates nuclear import of INTS9-11, and inositol hexaphosphate (IP6) is essential for final maturation.

Conclusions:

• BRAT1 and WDR73 are indispensable for the correct assembly and maturation of the Integrator cleavage module.
• Mutations in BRAT1, WDR73, and INTS11 cause neurodevelopmental disorders due to Integrator assembly defects.
• Inositol hexaphosphate (IP6) is identified as a crucial cofactor for the mature cleavage module.