RASA1 expression highlights Z/W dosage dynamics and gonadal development in chickens.

Area of Science:

• Genomics
• Developmental Biology
• Avian Genetics

Background:

• Avian sex chromosomes (Z and W) exhibit homologous genes with high sequence similarity.
• W-linked genes are often dose-sensitive and conserved to ensure balanced expression between sexes.

Purpose of the Study:

• To investigate the sequence characteristics, expression patterns, and functional roles of the RASA1 gene in chicken embryos.
• To determine the contribution of RASA1-Z and RASA1-W alleles to gene expression and cellular functions.

Main Methods:

• Quantitative analysis of RASA1 gene expression (mRNA and protein) in male and female chicken embryos.
• Gene knockdown and overexpression experiments for RASA1-Z and RASA1-W.
• Sex reversal experiments to assess RASA1's role in gonadal differentiation.
• Cell proliferation assays (CCK8) to evaluate RASA1 function.

Main Results:

• RASA1-Z showed higher expression in male gonads; RASA1-W compensated for total mRNA in females.
• RASA1 protein levels were significantly higher in males, with RASA1-W having minimal protein contribution.
• RASA1-Z knockdown decreased mRNA and protein; RASA1-W overexpression increased mRNA but not protein.
• RASA1 expression was not significantly altered in sex-reversed gonads.
• RASA1-Z promoted cell proliferation, while RASA1-W had little effect.

Conclusions:

• RASA1 primarily functions in cell proliferation and angiogenesis, not gonadal sex differentiation.
• RASA1-W contributes to transcript balance but not protein output, highlighting differential allelic function.
• The study elucidates the distinct roles of RASA1 alleles on avian sex chromosomes.