The mammalian SKIV2L RNA exosome is essential for early B cell development

Area of Science:

• Immunology
• Molecular Biology
• Genetics

Background:

• The SKIV2L RNA exosome complex is vital for RNA degradation in eukaryotes.
• Mutations in SKIV2L cause trichohepatoenteric syndrome (THES), a disorder with unknown mechanisms.
• THES patients exhibit multisystem involvement, including severe primary B cell immunodeficiency.

Purpose of the Study:

• To investigate the role of SKIV2L in B cell development and the pathogenesis of THES.
• To elucidate the molecular mechanisms underlying SKIV2L-associated immunodeficiency.

Main Methods:

• Studied a THES patient with SKIV2L mutations.
• Generated B cell-specific Skiv2l knockout mice (Skiv2lfl/flCd79a-Cre).
• Analyzed B cell populations, V(D)J recombination, and immunoglobulin heavy chain expression.

Main Results:

• THES patient showed severe B cell deficiency, hypogammaglobulinemia, and normal T/NK cell function.
• Skiv2l knockout mice lacked B-2 and B-1 B cells.
• Skiv2l deficiency caused pro-B cell cycle arrest, DNA damage, and impaired V(D)J recombination and μH expression.

Conclusions:

• SKIV2L is essential for early B cell development in humans and mice.
• Proper V(D)J recombination and Igh expression depend on SKIV2L activity.
• This highlights the molecular basis for THES-associated immunodeficiency.