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mall nuclear RNAs (snRNAs) play essential roles in spliceosome assembly and splicing. Most snRNAs are transcribed by the DNA-dependent RNA polymerase II (Pol II) and require 3' end endonucleolytic cleavage. We have previously shown that the Arabidopsis (Arabidopsis thaliana) Defective in snRNA Processing 1 (DSP1) complex, composed of at least five subunits, is responsible for snRNA 3' maturation and is essential for plant development. Yet, it remains unclear how DSP1 complex subunits act together to process snRNAs. Here we show that DSP4, a member of the metallo-β-lactamase family, physically interacts with DSP1 through its β-Casp domain. Null dsp4-1 mutants have pleiotropic developmental defects, including impaired pollen development, and reduced pre-snRNA transcription and 3' maturation, resembling the phenotype of the dsp1-1 mutant. Interestingly, dsp1-1 dsp4-1 double mutants exhibit complete male sterility and reduced pre-snRNA transcription and 3' end maturation, unlike dsp1-1 or dsp4-1. In addition, Pol II occupancy at snRNA loci is lower in dsp1-1 dsp4-1 than in either single mutant. We also detected miscleaved pre-snRNAs in dsp1-1 dsp4-1, but not in dsp1-1 or dsp4-1. Taken together, these data reveal that DSP1 and DSP4 function is essential for pollen development, and that the two cooperatively promote pre-snRNA transcription and 3' end processing efficiency and accuracy.
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This content will become publicly available on January 1, 2026
Bridging the Knowledge Gap: Utilization of Mediator Subunits for Crop Improvement
ABSTRACT The Mediator complex is a multisubunit transcription coregulator that transfers regulatory signals from different transcription factors to RNA polymerase II (Pol II) to control Pol II‐dependent transcription in eukaryotes. Studies on Arabidopsis Mediator subunits have revealed their unique or overlapping functions in various aspects of plant growth, stress adaptation and metabolite homeostasis. Therefore, the utilization of the plant Mediator complex for crop improvement has been of great interest. Advances in genome editing and sequencing techniques have expedited the characterization of Mediator subunits in economically important crops such as tomato, rice, wheat, soybean, sugarcane, pea, chickpea, rapeseed and hop. In this review, we summarize recent progress in understanding the molecular mechanisms of how the Mediator complex regulates crop growth, development and adaptation to environmental stress. We also discuss the conserved and diverse functions of the Mediator complex in different plant species. In addition, we propose several future research directions to deepen our understanding of the important roles of Mediator subunits and their interacting proteins, which would provide promising targets for genetic modification to develop new cultivars with desirable agronomic traits.
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- Award ID(s):
- 2142898
- PAR ID:
- 10572115
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- Plant, Cell & Environment
- Volume:
- 48
- Issue:
- 1
- ISSN:
- 0140-7791
- Page Range / eLocation ID:
- 213 to 225
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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