Characteristics of N6-methyladenosine modification during sexual reproduction of Chlamydomonas reinhardtii

Abstract

The unicellular green alga Chlamydomonas reinhardtii (referred to as Chlamydomonas throughout) is an ideal model organism which possesses both plant and animal attribute for studying the fundamental processes such as photosynthesis, sexual reproduction and life cycle etc. N6-methyladenosine (m6A) is the most prevalent mRNA modification and plays important roles during sexual reproduction in animals and plants. However, the pattern and function of m6A modification during Chlamydomonas sexual reproduction is still unknown. Here, we performed transcriptome and MeRIP sequencing on the six samples from different stages during sexual reproduction of Chlamydomonas life cycle. The results showed that m6A occurs widely at the main motif of UGKAM (K= U/G, M= A/C) in Chlamydomonas mRNA. Moreover, m6A peak in Chlamydomonas mRNA is mainly enriched in the 3UTR region and negatively correlated with the abundance of the transcripts at each stage. Especially, genes in microtubule-associated pathway showed a significant negative correlation between gene expression level and m6A level, indicating the influences of m6A modification on sexual reproduction and life cycle of Chlamydomonas through regulating microtubule-based movement. In summary, our findings first demonstrate the distributions and the functions of m6A modification in Chlamydomonas and provide new insights into the understandings of m6A modification in the process of sexual reproduction in other plant organisms evolutionarily.