Insulin-like androgenic gland hormone 1 (IAG1) regulates sexual differentiation in a hermaphrodite shrimp through feedback to neuroendocrine factors

RNAi Reveals Role of Insulin-Like Androgenic Gland Hormone 2 (IAG2) in Sexual Differentiation and Growth in Hermaphrodite Shrimp

“…A total of 15 shrimp (carapace length: 3.21 ± 0.35 mm, bodyweight: 50.40 ± 12.14 mg) were randomly and equally assigned to the following 3 treatment groups (n = 5): dsRNA Lvit-IAG2-injected, dsRNA GFP-injected, and PBS. The delivery of dsRNA (2 µg/g) (Liu et al, 2020) was by intramuscular injection in the abdominal segment of shrimp, and the PBS-injected treatment received an equivalent volume of PBS. Sampling was performed 24 h after injection.…”

“…The relative expression of Lvit-IAG2 in the AG during gonadal development was also assessed through qRT-PCR (Figure 3B). Notably, the expression levels of Lvit-IAG2 (Liu et al, 2020). 4).…”

“…In decapod species, IAG was first identified in the androgenic gland (AG) of the red-claw crayfish Cherax quadricarinatus in 2007 (Manor et al, 2007). Since then, numerous studies have found IAG in dioecious (Ventura et al, 2009;Rosen et al, 2010;Ventura et al, 2012;Chung, 2014;Huang et al, 2014), parthenogenetic (Levy et al, 2017), and hermaphroditic (Zhang et al, 2017;Levy et al, 2020a;Liu et al, 2020) species. Furthermore, its critical role in sexual differentiation has been properly studied via loss-of-function experiments (Ventura et al, 2012;Zmora and Chung, 2014;Priyadarshi et al, 2017;Fu et al, 2020).…”

“…The very low but detectable expression of Lw-IAG during the euhermaphrodite phases suggested that Lw-IAG was possibly responsible for the maintenance of the male reproductive activity in euhermaphrodite phase. Recently, a transcriptomic study identified two insulin-like peptide (ILP) transcripts (Lvit-IAG1 and Lvit-IAG2) in the peppermint shrimp Lysmata vittata (Bao et al, 2020), and biological functions of Lvit-IAG1 have been explored in detail (Liu et al, 2020). In L.vittata, silencing Lvit-IAG1 impeded development of male-related phenotypes (appendices masculinae (AM) and male gonopores) while suppressing the germ cells at the primary spermatocyte stage, demonstrating that Lvit-IAG1 was indeed a functional IAG.…”

“…In L.vittata, silencing Lvit-IAG1 impeded development of male-related phenotypes (appendices masculinae (AM) and male gonopores) while suppressing the germ cells at the primary spermatocyte stage, demonstrating that Lvit-IAG1 was indeed a functional IAG. Meanwhile, Lvit-IAG1 was also suggested to regulate the ovarian development by inhibiting Lvit-GIHs and Lvit-CFSHs expression in the eyestalk ganglion (Liu et al, 2020). In decapods, four types of insulin and related peptides were identified: insulinlike androgenic gland hormone (IAG), insulin, relaxins, and gonadulins (Veenstra, 2020).…”