The BAF chromatin remodeling complex licenses planarian stem cells access to ectodermal and mesodermal cell fates

Area of Science:

• Stem cell biology
• Developmental biology
• Chromatin regulation

Background:

• Planarian adult stem cells (ASCs), known as neoblasts, possess self-renewal and multipotency.
• Chromatin remodeling complexes and transcription factors regulate gene expression and cell fate.
• Previous studies linked BAF complex component RNAi to increased ASCs and regeneration failure in planarians.

Purpose of the Study:

• To investigate the role of the BAF chromatin remodeling complex in planarian neoblasts.
• To understand how BAF complex subunits brg-1 and smarcc2 regulate gene expression and cell fate in ASCs.

Main Methods:

• ATAC and RNA sequencing were performed on purified planarian neoblasts.
• Neoblasts were deficient for BAF complex subunits brg-1 and smarcc2 via RNAi.
• Gene accessibility and transcription were analyzed in relation to BAF complex function.

Main Results:

• The BAF complex enhances chromatin accessibility and transcription at target genes in planarian neoblasts.
• BAF complex deficiency impairs access to genes essential for mesoderm and ectoderm lineage development (muscle, neural, epithelial).
• BAF complex depletion leads to disrupted differentiation and regeneration, with no observed effect on endodermal lineages.

Conclusions:

• The BAF complex plays a critical role in regulating cell fate decisions in planarian ASCs.
• This complex is essential for neoblasts to access and transcribe genes required for specific lineage differentiation.
• Understanding BAF complex function provides insights into stem cell regulation and regeneration mechanisms.