Identification and characterization of a Masculinizer (Masc) gene involved in sex differentiation in Artemia

• Published in: Gene 2017-05, Vol.614, p.56-64
• Main Authors: Li, Dong-Rui, Ye, Hui-Li, Yang, Jin-Shu, Yang, Fan, Wang, Mo-Ran, De Vos, Stephanie, Vuylsteke, Marnik, Sorgeloos, Patrick, Van Stappen, Gilbert, Bossier, Peter, Yang, Wei-Jun
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Artemia - embryology; Artemia - genetics; Artemia - metabolism; Artemia franciscana; Arthropod Proteins - genetics; Arthropod Proteins - metabolism; Base Sequence; Blotting, Western; Bombyx mori; chromosomes; double-stranded RNA; Embryo, Nonmammalian - embryology; Embryo, Nonmammalian - metabolism; embryogenesis; environmental factors; evolution; Female; fluorescent antibody technique; Gene Expression Regulation, Developmental; genes; hatching; invertebrates; Larva - genetics; Male; Masculinizer; messenger RNA; nauplii; open reading frames; parthenogenesis; Parthenogenesis - genetics; Parthenogenetic Artemia; ploidy; progeny; quantitative polymerase chain reaction; Reverse Transcriptase Polymerase Chain Reaction; RNA Interference; sequence analysis; Sequence Analysis, DNA; Sequence Homology, Amino Acid; sex determination; Sex Determination Processes - genetics; Sex Differentiation - genetics; Sexual Artemia; Sexual determination; sexual development; silkworms; Time Factors; Western blotting; zinc finger motif
• ISSN: 0378-1119; 1879-0038
• DOI: 10.1016/j.gene.2017.03.010

The sex of relatively primitive animals such as invertebrates is mostly determined by environmental factors and chromosome ploidy. Heteromorphic chromosomes may also play an important role, as in the ZW system in lepidopterans. However, the mechanisms of these various sex determination systems are still largely undefined. In the present study, a Masculinizer gene (Ar-Masc) was identified in the crustacean Artemia franciscana Kellogg 1906. Sequence analysis revealed that the 1140-bp full-length open reading frame of Ar-Masc encodes a 380-aa protein containing two CCCH-type zinc finger domains having a high degree of shared identities with the MASC protein characterized in the silkworm Bombyx mori, which has been determined to participate in the production of male-specific splice variants. Furthermore, although Ar-Masc could be detected in almost all stages in both sexual and parthenogenetic Artemia, there were significant variations in expression between these two reproductive modes. Firstly, qRT-PCR and Western blot analysis showed that levels of both Ar-Masc mRNA and protein in sexual nauplii were much higher than in parthenogenetic nauplii throughout the hatching process. Secondly, both sexual and parthenogenetic Artemia had decreased levels of Ar-Masc along with the embryonic developmental stages, while the sexual ones had a relatively higher and more stable expression than those of parthenogenetic ones. Thirdly, immunofluorescence analysis determined that sexual individuals had higher levels of Ar-MASC protein than parthenogenetic individuals during embryonic development. Lastly, RNA interference with dsRNA showed that gene silencing of Ar-Masc in sexual A. franciscana caused the female-male ratio of progeny to be 2.19:1. These data suggest that Ar-Masc participates in the process of sex determination in A. franciscana, and provide insight into the evolution of sex determination in sexual organisms. •A sex-related gene “Ar-Masc” gene was firstly identified in A. franciscana;•Ar-Masc shows higher expression levels in sexual Artemia than in parthenogenetic nauplii throughout the hatching process;•Ar-Masc exhibits relatively higher expression in sexual Artemia than in parthenogenetic during the embryonic development;•Gene silencing of Ar-Masc in sexual A. franciscana induced the dominance of female offsprings.