NF45 and NF90/NF110 coordinately regulate ESC pluripotency and differentiation.

Area of Science:

• Developmental Biology
• Stem Cell Biology
• Molecular Biology

Background:

• Embryonic stem cell (ESC) regulation is complex, with post-transcriptional and translational mechanisms, particularly RNA binding proteins (RBPs), being understudied.
• The precise roles of RBPs in maintaining pluripotency and controlling differentiation in ESCs remain largely unknown.

Purpose of the Study:

• To investigate the function of RBPs in ESC pluripotency and differentiation.
• To identify specific RBPs involved in regulating the balance between self-renewal and differentiation in ESCs.

Main Methods:

• Performed an unbiased RNA interference (RNAi) screen of RBPs in an ESC differentiation assay.
• Utilized knockout (KO) ESC models (NF45 KO, NF90 + NF110 KO, NF110 KO) for functional characterization.
• Conducted RNA immunoprecipitation sequencing (RIP-seq) to identify direct targets of NF90/NF110.

Main Results:

• Knockdown of NF45 (Ilf2) and NF90/NF110 (Ilf3) promoted ESC differentiation towards an epiblast-like state.
• Loss of NF45 or NF90 + NF110 impaired ESC proliferation and dysregulated differentiation.
• NF45 and NF90/NF110 physically interact and influence each other's expression, forming feedback loops.
• NF90/NF110 were found to directly regulate genes involved in proliferation, differentiation, and RNA processing.

Conclusions:

• NF45, NF90, and NF110 are critical regulators of ESC pluripotency and differentiation.
• These RBPs function in overlapping and independent feedback loops to balance self-renewal and differentiation cues.
• The findings reveal novel post-transcriptional mechanisms governing ESC fate decisions.