Maize Dek15 Encodes the Cohesin-Loading Complex Subunit SCC4 and Is Essential for Chromosome Segregation and Kernel...

Area of Science:

• Plant genetics
• Molecular biology
• Cell biology

Background:

• Cohesin complexes are vital for accurate chromosome segregation in cell division.
• Understanding plant cohesin components, particularly in maize (Zea mays), is limited.

Purpose of the Study:

• To identify the gene responsible for the maize mutant defective kernel 15 (dek15).
• To elucidate the function of the SISTER CHROMATID COHESION PROTEIN 4 (SCC4) in maize development and chromosome segregation.

Main Methods:

• Positional cloning to identify the dek15 gene.
• Phenotypic analysis of dek15 kernels, including cell counts and size.
• Microscopic examination of chromosome segregation in dek15 mutants.
• Gene expression analysis using quantitative methods.
• Yeast two-hybrid screening to identify interacting proteins.

Main Results:

• The dek15 mutation was identified as a homolog of SISTER CHROMATID COHESION PROTEIN 4 (SCC4).
• dek15 mutants exhibit reduced cell numbers, variable cell size, disrupted cell cycles, and endoreduplication defects.
• Precocious sister chromatid separation, chromosome misalignments, lagging chromosomes, micronuclei, and aneuploidy were observed.
• Loss of DEK15/SCC4 function altered gene expression related to cell cycle, stress response, and organic synthesis.
• SCC4 interacts with chromatin remodeling proteins CHB102, CHB105, and CHB106.

Conclusions:

• DEK15/SCC4 plays a critical role in mitotic chromosome segregation and maize kernel development.
• SCC4 is essential for maintaining genome stability during cell division in plants.
• Interactions with chromatin remodelers suggest a mechanism for cohesin loading onto plant chromatin.