反田真登 博士研究員（米国ペンシルバニア大学）

2024年11月14日(木) 16:00 より 17:00 まで

明大寺地区1階 会議室 (111)

進化ゲノミクス研究室　重信秀治 (x7670)

Social insects are important model systems for studying the mechanisms of behavioral and physiological plasticity associated with caste differentiation in response to social environments. However, genome editing technologies are not yet fully developed in these species, making molecular biological and genetic analyses challenging compared to studies in widely-used model organisms. Improving genome editing techniques will be essential for future research to address these scientific questions.

The ant Harpegnathos saltator is a social insect species in which caste differentiation occurs during the adult stage. Adults initially emerge as non-reproductive workers, and some subsequently differentiate into a reproductive caste called gamergate. However, the molecular mechanisms underlying this caste differentiation into gamergates remain unclear.

Although there has been a single report of gene knockout in Harpegnathos, more advanced genome editing has not yet been reported. We explored an optimal microinjection method for Harpegnathos and successfully achieved knock-in of foreign sequences at the egg stage using CRISPR-Cas9-based genome editing. Additionally, we developed a method to efficiently deliver single-stranded donor DNA to target sites and another for selecting target genes suitable for genome editing at the embryonic stage, both of which improved mutation efficiency. Furthermore, to anticipate the need for complex donor DNA in future studies, we established a new plasmid construction method that expands the versatility of the Golden Gate assembly (Sorida and Bonasio, Cell Reports Methods, 2023). We also discovered an alternative method for establishing a subtype of gamergates and identified differentially expressed genes (DEGs) between two types of gamergates via RNA-seq analysis. Preliminary observations indicate that this subtype of gamergate exhibits some worker-like behaviors, with gene expression patterns resembling a hybrid state between typical gamergates and workers.

In summary, we have improved genome editing techniques and laid a foundation for investigating the mechanisms underlying caste differentiation.
 
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