Spindle-E is essential for gametogenesis in the silkworm, Bombyx mori

Area of Science:

• Genetics and Genomics
• Developmental Biology
• Molecular Biology

Background:

• The PIWI-interacting RNA (piRNA) pathway is essential for genomic integrity and gametogenesis.
• The Spindle-E (Spn-E) gene is a known participant in the piRNA pathway.
• Understanding Spn-E's role in non-Drosophila species is important for comparative genomics.

Purpose of the Study:

• To investigate the function of the Spindle-E (Spn-E) gene in the model lepidopteran insect, Bombyx mori.
• To analyze the expression pattern and localization of BmSpn-E.
• To determine the impact of BmSpn-E loss-of-function on gonadal development and gametogenesis.

Main Methods:

• Functional analysis of BmSpn-E in Bombyx mori.
• Generation of BmSpn-E mutants using a binary transgenic CRISPR/Cas9 system.
• Analysis of gene expression, transposon derepression, gonad size, germ cell number, apoptosis (TUNEL staining), and developmental timing.

Main Results:

• BmSpn-E exhibits ubiquitous expression, with high levels in gonads, localized in both germ and somatic cells.
• Loss of BmSpn-E results in transposon derepression, smaller gonads, reduced germ cell numbers, and enhanced apoptosis.
• BmSpn-E mutation impacts gonadal development and gametogenesis early in the larval stage.

Conclusions:

• BmSpn-E plays a vital role in maintaining gonadal development and gametogenesis in Bombyx mori.
• The findings highlight Spn-E's conserved function in the piRNA pathway across different insect species.
• This study provides the first evidence for BmSpn-E's critical functions in lepidopteran reproduction.