TY  - JOUR
A1  - Li, Chenxin
A1  - Xu, Hengping
A1  - Fu, Fang-Fang
A1  - Russell, Scott D
A1  - Sundaresan, Venkatesan
A1  - Gent, Jonathan Isaiah
T1  - Genome-wide redistribution of 24-nt siRNAs in rice gametes
Y1  - 2020/01/02 
JF  - Genome Research 
JO  - Genome Research 
DO  - 10.1101/gr.253674.119 
SP  - gr.253674.119 
UR  - http://genome.cshlp.org/content/early/2020/01/02/gr.253674.119.abstract 
N2  - Gametes constitute a critical stage of the plant life cycle during which the genome undergoes reprogramming in preparation for embryogenesis. Here we examined genome-wide distributions of small RNAs in the sperm and egg cells of rice. We found that 24-nt siRNAs, which are a hallmark of RNA-directed DNA methylation (RdDM) in plants, were depleted from heterochromatin boundaries in both gametes relative to vegetative tissues, reminiscent of siRNA patterns in DDM1-type nucleosome remodeler mutants. In sperm cells, 24-nt siRNAs were spread across heterochromatic regions, while in egg cells, 24-nt siRNAs were concentrated at a smaller number of heterochromatic loci throughout the genome, especially at loci which also produced siRNAs in other tissues. In both gametes, patterns of CHH methylation, typically a strong indicator of RdDM, were similar to vegetative tissues, although lower in magnitude. These findings indicate that the small RNA transcriptome undergoes large-scale redistribution in both male and female gametes, which is not correlated with recruitment of DNA methyltransferases in gametes and suggestive of unexplored regulatory activities of gamete small RNAs. 
ER  -