Male Sexual Development and the Androgenic Gland: Novel Insights through the de novo Assembled Transcriptome of the Eastern Spiny Lobster,<b><i> Sagmariasus verreauxi</i></b>

Abstract

The Eastern spiny lobster, Sagmariasus verreauxi, is commercially important in fisheries, with growing aquaculture potential, driving an interest to better understand male sexual differentiation. Amongst the Decapoda, the androgenic gland (AG) and the insulin-like androgenic gland hormone (IAG) have a well-defined function in male sexual differentiation. However, IAG is not a sex determinant and therefore must be considered as part of a broader, integrated pathway. This work uses a transcriptomic, multi-tissue approach to provide an integrated description of male-biased expression as mediated through the AG. Transcriptomic analyses demonstrate that IAG expression is stage- and eyestalk-regulated (low in immature, high in mature and 6-times higher in hypertrophied glands), with IAG being the predominant AG-specific factor. The low expression of this key factor in immature males suggests the involvement of other tissues in male sexual differentiation. Across tissues, the gonad (87.8%) and antennal gland (73.5%) show the highest male-biased differential expression of transcripts and also express 4 sex-determination regulators, known as Dmrts, with broader expression of Sv-Sxl and Sv-TRA-2. In order to better understand male sexual differentiation, tissues other than the AG must also be considered. This research highlights the gonad and antennal gland as showing significant male-biased expression patterns, including the Sv-Dmrts.

CYP450s analysis across spiny lobster metamorphosis identifies a long sought missing link in crustacean development

“…The lengthy transition, the large-sized larvae and their transparency enable clear molt staging by gut retraction. The availability of transcriptomic data for both the larval metamorphic transition at high resolution [35], alongside tissues of juveniles and adults from this species [44][45][46][47][48][49] enables thorough examination of expression patterns and correlation with spatial-temporal expression.…”

“…Where ORF was predicted to be partial, iterative tBLASTn searches using CLC Genomics Workbench (Qiagen, version 8.0.3), against the transcriptome of both developmental stages [35] and juvenile and mature tissues [44,48], were performed in order to identify flanking regions. The predicted ORFs were searched for CYP450 domains using PFAM database in CLC Genomics Workbench.…”

“…We identified 43 putative CYP450s (11 partial, ranging in size from 311 to 441 aa and 32 complete, ranging in size from 485 to 562 aa) in the Eastern spiny lobster S. verreauxi transcriptome, assembled from RNA extracted from whole individuals sampled across metamorphosis [35] as well as from various tissues of juvenile and adult individuals [44,48].…”

“…Taking advantage of the available libraries for different well-defined metamorphic stages [35], as well as juvenile and adult tissues [44,48], we assessed the CYP450s expression pattern during metamorphosis in S. verreauxi.…”

Biomolecular changes that occur in the antennal gland of the giant freshwater prawn (Machrobrachium rosenbergii)

“…The most compelling evidence of a sex pheromone has been demonstrated from research on the blue crab, Callinectes sapidus , where N -acetylglucosamino-1,5-lactone (NAGL) present in the female AnG urine at intermolt and premolt, can activate physiological and behavioural responses in conspecifics [12]. Supporting a key role for the AnG in sex pheromone release, a recent transcriptomic screen of several tissues from the Eastern spiny lobster ( Sagmariasus verreauxi ), found that the most significantly biased transcript expression between males and females is within the AnG (other than the gonad) [13]. However, a large-scale analysis of this gland utilising a combined approach of transcriptomic, proteomic and metabolomic methodologies has not been performed to date.…”