Specific and conserved roles of TAp73 during zebrafish development

Area of Science:

• Developmental Biology
• Molecular Genetics
• Comparative Genomics

Background:

• The p53 family of transcription factors (p53, p63, p73) regulates critical cellular processes like proliferation, survival, and differentiation.
• Previous studies on zebrafish p63 reported only N-terminally truncated isoforms (DeltaNp63).
• The expression and function of p73 in zebrafish development remained largely uncharacterized.

Purpose of the Study:

• To isolate and characterize zebrafish p73.
• To investigate the expression pattern of p73 during zebrafish development.
• To determine the functional roles of TAp73 in zebrafish embryogenesis through gain- and loss-of-function studies.

Main Methods:

• Isolation and characterization of zebrafish p73.
• Analysis of p73 expression patterns using transcript analysis during zebrafish development.
• Gain-of-function experiments via TAp73alpha mRNA injection.
• Loss-of-function experiments using antisense morpholino oligonucleotides against TAp73 transcripts.

Main Results:

• Zebrafish p73 is predominantly expressed as transactivating isoforms (TAp73).
• p73 exhibits a restricted expression pattern in the olfactory system, telencephalon, dorsal diencephalon, pronephric ducts, differentiating slow muscle cells, and pharyngeal endoderm.
• TAp73alpha overexpression does not induce apoptosis in zebrafish embryos, unlike p53.
• TAp73 is essential for the proper development of the olfactory system, telencephalon, and pharyngeal arches.

Conclusions:

• Zebrafish p73 is mainly present as TAp73 isoforms, differing from the reported p63 isoforms.
• p73 plays crucial, class-specific roles in the development of sensory organs and the central nervous system in zebrafish.
• The findings highlight both conserved and unique functions of p73 across vertebrate development.