Variable expression of nuclear receptor coactivator 4 (NcoA4) during mouse embryonic development

Area of Science:

• Molecular Biology
• Developmental Biology
• Genetics

Background:

• Nuclear receptor coactivator 4 (NcoA4) enhances transcription factors like aryl hydrocarbon receptor (AhR) and androgen receptor (AR).
• AhR and AR are crucial for embryonic development, with specific expression timelines post-conception.

Purpose of the Study:

• To investigate the expression pattern of NcoA4 during mouse embryonic development (E9.5-E17.5).
• To assess the functional role of NcoA4 in modulating AhR and AR activity in vivo.

Main Methods:

• Reverse transcription-polymerase chain reaction (RT-PCR) to detect NcoA4 transcripts.
• Western blot analysis to confirm NcoA4 protein expression.
• Immunohistochemistry to visualize NcoA4 localization in embryonic tissues.
• COS cell transfections to study NcoA4's effect on AhR and AR activity.

Main Results:

• Full-length NcoA4 transcript and protein were detected across all embryonic stages and adult tissues.
• NcoA4 protein expression increased in later embryonic stages (E15.5-E17.5).
• Murine NcoA4 lacks the LXXLL motif found in human NcoA4, impacting AR interaction.
• NcoA4 significantly boosted AhR activity (5-fold) and moderately enhanced AR activity (1.5-fold) in COS cells.

Conclusions:

• NcoA4 is ubiquitously expressed throughout mouse development, suggesting a vital role.
• NcoA4 primarily influences AhR activity during development, with a lesser effect on AR.
• The absence of the LXXLL motif in murine NcoA4 may explain its differential impact on AR activity.