Ovule identity mediated by pre-mRNA processing in Arabidopsis

Area of Science:

• Plant reproductive biology
• Molecular genetics
• Developmental biology

Background:

• Ovules are crucial for plant reproduction and seed development.
• D-class genes (SHP1, SHP2, STK) specify ovule identity in Arabidopsis thaliana.
• HUA-PEP activity, involving RNA-binding proteins, regulates floral organ identity via AG pre-mRNA processing.

Purpose of the Study:

• To investigate the role of HUA-PEP activity in ovule development and morphogenesis.
• To elucidate the molecular mechanisms underlying HUA-PEP's function in ovule specification.

Main Methods:

• Analysis of severe hua-pep mutant phenotypes.
• Molecular and genome-wide profiling to assess D-class gene transcript levels.
• Investigation of interactions between HUA-PEP members and the RNAPII CTD regulator CPL1.

Main Results:

• Severe hua-pep mutants exhibit ovule homeotic transformations into flower-like structures.
• D-class gene activity (SHP1, SHP2, STK) is significantly reduced in hua-pep mutants.
• Prematurely terminated D-class gene transcripts accumulate, indicating pre-mRNA processing defects.
• HUA-PEP members interact with CPL1, suggesting co-transcriptional regulation.

Conclusions:

• HUA-PEP activity is essential for proper ovule morphogenesis and identity.
• Misregulation of D-class gene pre-mRNA processing by HUA-PEP causes ovule developmental defects.
• HUA-PEP likely acts co-transcriptionally, coordinating RNA processing and transcription via CPL1 interaction.