Transcriptional Profiles of Diploid Mutant Apis mellifera Embryos after Knockout of csd by CRISPR/Cas9

Abstract

In honey bees, complementary sex determiner (csd) is the primary signal of sex determination. Its allelic composition is heterozygous in females, and hemizygous or homozygous in males. To explore the transcriptome differences after sex differentiation between males and females, with genetic differences excluded, csd in fertilized embryos was knocked out by CRISPR/Cas9. The diploid mutant males at 24 h, 48 h, 72 h, and 96 h after egg laying (AEL) and the mock-treated females derived from the same fertilized queen were investigated through RNA-seq. Mutations were detected in the target sequence in diploid mutants. The diploid mutant drones had typical male morphological characteristics and gonads. Transcriptome analysis showed that several female-biased genes, such as worker-enriched antennal (Wat), vitellogenin (Vg), and some venom-related genes, were down-regulated in the diploid mutant males. In contrast, some male-biased genes, such as takeout and apolipophorin-III-like protein (A4), had higher expressions in the diploid mutant males. Weighted gene co-expression network analysis (WGCNA) indicated that there might be interactions between csd and fruitless (fru), feminizer (fem) and hexamerin 70c (hex70c), transformer-2 (tra2) and troponin T (TpnT). The information provided by this study will benefit further research on the sex dimorphism and development of honey bees and other insects in Hymenoptera.

Advances in Editing Silkworms (Bombyx mori) Genome by Using the CRISPR-Cas System

“…On the other hand, the expression level of several specific female-biased genes was lower. Their data also confirmed that csd interacts with certain genes, such as fruitless, troponin T, and transformer-2 just to mention a few [81].…”

“…The bees that are heterozygous at this specific locus are females, while the males are homozygous or hemizygous [80]. In a recent study, Wang et al (2021) [81] used the CRISPR-Cas9 tool in order to knock out the csd gene and, thus, eliminated the genetic difference between females and males. Subsequently, they aimed to observe the transcriptome difference between the two sexes in this particular genetic background.…”

Revealing phosphorylation regulatory networks during embryogenesis of honey bee worker and drone (Apis mellifera)

“…Due to the easily accessible conditions for embryonic development (34°C temperature, 80% relative humidity) ( Nelson, 1915 ; Winston, 1987 ), the embryo is an ideal model used in honey bee genetic research ( DuPraw, 1967 ). Several works have been reported to understand honey bee embryonic development from describing morphology to dissecting molecular underpinnings, such as detailed morphological differentiation ( Fleig and Sander, 1986a ; Woyke, 1998 ; Katzav-Gozansky et al, 2003 ), transcriptional modification ( Pires et al, 2016 ; Netschitailo et al, 2022 ), and genome editing ( Kohno et al, 2016 ; Hu et al, 2019 ; Nie et al, 2021 ; Wang et al, 2021 ; Değirmenci et al, 2022 ). Recently, our works on proteomics elucidated that embryos at different ages have tailored distinct proteome arsenals to underline the age-specific physiological demands of honey bees ( Fang et al, 2014 ; Fang et al, 2015 ).…”