POP-1 controls axis formation during early gonadogenesis in C. elegans

Area of Science:

• Developmental Biology
• Genetics
• Cell Biology

Background:

• The C. elegans gonad's shape and polarity are established by asymmetric divisions of somatic gonadal precursor cells Z1 and Z4.
• These divisions generate leader cells that regulate gonad shape and establish proximal-distal axes.

Purpose of the Study:

• To investigate the role of the TCF/LEF-1 transcription factor POP-1 in establishing gonad polarity.
• To identify mutations affecting POP-1 function in gonad development.

Main Methods:

• Genetic analysis of novel pop-1 alleles (pop-1(Sys)) causing symmetrical cell divisions.
• RNA interference (RNAi) to assess zygotic pop-1 function.
• Analysis of Wnt pathway regulators wrm-1 and lit-1.

Main Results:

• Two pop-1 alleles, pop-1(q645) and pop-1(q624), were identified, causing symmetrical Z1/Z4 divisions and affecting gonad axis formation.
• pop-1(q645) affects the beta-catenin binding domain, while pop-1(q624) affects the DNA binding domain.
• Zygotic pop-1(RNAi) confirmed its role in Z1/Z4 asymmetry and revealed roles in leader cell migration.
• wrm-1 and lit-1 are required for POP-1 function in gonad asymmetry.

Conclusions:

• POP-1 is a key regulator of the first asymmetric division of Z1/Z4 cells, controlling proximal-distal axis formation in the C. elegans gonad.
• This finding expands the known roles of Wnt signaling in establishing polarity beyond anterior-posterior axes.