Pre-rRNA processing and its response to temperature stress in maize.

Area of Science:

• Molecular Biology
• Plant Science
• Genetics

Background:

• Ribosome biogenesis is crucial for eukaryotic cell function and involves pre-ribonucleic acid (pre-rRNA) processing.
• Understanding pre-rRNA processing in maize, a vital crop, is essential but currently limited.
• Existing knowledge of pre-rRNA processing pathways is primarily derived from yeast and mammals.

Purpose of the Study:

• To elucidate the specific pre-rRNA processing sites and pathways in maize.
• To identify critical endonucleolytic cleavage sites and intermediate pre-rRNA molecules.
• To compare maize pre-rRNA processing with that of other organisms and investigate stress responses.

Main Methods:

• Circular reverse-transcription PCR (cRT-PCR) was employed to identify pre-rRNA intermediates.
• Northern blot analysis was used to confirm and characterize pre-rRNA processing steps.
• Comparative analysis with yeast and mammalian models was performed.

Main Results:

• Two distinct pathways for 35S pre-rRNA processing were identified in maize.
• The processing of 27SA pre-rRNA was found to occur via two pathways, differing in the order of ITS1 removal and ITS2 cleavage.
• A novel 27SA pre-rRNA processing mechanism, unique to maize and higher plants, was discovered.
• Maize demonstrated modulation of pre-rRNA processing under chilling and heat stress, evidenced by reduced P-A3 intermediate levels.

Conclusions:

• Maize possesses unique pre-rRNA processing mechanisms distinct from yeast and mammals.
• The identified pathways provide a detailed model for ribosome biogenesis in maize.
• Pre-rRNA processing in maize is adaptable to environmental stresses, impacting ribosome production.
• This research lays the groundwork for future studies on maize ribosome biogenesis and stress adaptation.