Vitellogenin Gene Research Articles

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

Insulin-like androgenic gland hormone (IAG) is the most widely known hormone that regulates sexual differentiation in crustaceans. Previously, a transcriptome study described two transcripts of IAGs (Lvit-IAG1 and Lvit-IAG2) in the peppermint shrimp Lysmata vittata, a species characterized by a rare reproductive system of protandric simultaneous hermaphroditism (PSH). Herein, we explored the function of Lvit-IAG2 via RNA interference (RNAi) experiments, and then compared the functional differences between the two IAGs. We demonstrated that Lvit-IAG2 positively regulated the expression of crustacean hyperglycemic hormone (Lvit-CHH) in eyestalk ganglion but exhibited no significant effect on the expression of gonad-inhibiting hormone (Lvit-GIHs) and crustacean female sex hormone (Lvit-CFSHs). Besides, Lvit-IAG2 gene knockdown caused degeneration in appendices masculinae (AM) and suppressed germ cells at the secondary spermatocyte stage. Moreover, silencing the Lvit-IAG2 gene impeded ovarian development, including smaller previtellogenic oocytes, and lower expression of vitellogenin (Lvit-Vg) gene in hepatopancreas and vitellogenin receptor (Lvit-VgR) gene in the ovarian region. Notably, silencing the Lvit-IAG2 gene impeded individual growth of the species. Collectively, findings from this study demonstrate that Lvit-IAG2 and Lvit-IAG1 coordinatively function to modulate sexual differentiation in L. vittata; meanwhile, Lvit-IAG2 stimulates the growth of the PSH species.

Immunity and physiological changes in adult honey bees (Apis mellifera) infected with Nosema ceranae: The natural colony environment

Nosema ceranae is a microsporidium that infects Apis mellifera, causing diverse physiological and behavioral alterations. Given the existence of individual and social mechanisms to reduce infection and fungal spread in the colony, bees may respond differently to infection depending on their rearing conditions. In this study, we investigated the effect of N. ceranae in honey bee foragers naturally infected with different fungal loads in a tropical region. In addition, we explored the effects of N. ceranae artificially infected young bees placed in a healthy colony under field conditions. Honey bees naturally infected with higher loads of N. ceranae showed downregulation of genes from Toll and IMD immune pathways and antimicrobial peptide (AMP) genes, but hemolymph total protein amount and Vitellogenin (Vg) titers were not affected. Artificially infected bees spread N. ceranae to the controls in the colony, but fungal loads were generally lower than those observed in cages, probably because of social immunity. Although no significant changes in mRNA levels of AMP-encoding were observed, N. ceranae artificially infected bees showed downregulation of miR-989 (an immune-related microRNA), lower vitellogenin gene expression, and decreased hemolymph Vg titers. Our results demonstrate for the first time that natural infection by N. ceranae suppresses the immune system of honey bee foragers in the field. This parasite is detrimental to the immune system of young and old bees, and disease spread, mitigation and containment will depend on the colony environment.

DNMT3.1 controls trade-offs between growth, reproduction, and life span under starved conditions in Daphnia magna

The cladoceran crustacean Daphnia has long been a model of energy allocation studies due to its important position in the trophic cascade of freshwater ecosystems. However, the loci for controlling energy allocation between life history traits still remain unknown. Here, we report CRISPR/Cas-mediated target mutagenesis of DNA methyltransferase 3.1 (DNMT3.1) that is upregulated in response to caloric restriction in Daphnia magna. The resulting biallelic mutant is viable and did not show any change in growth rate, reproduction, and longevity under nutrient rich conditions. In contrast, under starved conditions, the growth rate of this DNMT3.1 mutant was increased but its reproduction was reciprocally reduced compared to the wild type when the growth and reproduction activities competed during a period from instar 4 to 8. The life span of this mutant was significantly shorter than that of the wild type. We also compared transcriptomes between DNMT3.1 mutant and wild type under nutrient-rich and starved conditions. Consistent with the DNMT3.1 mutant phenotypes, the starved condition led to changes in the transcriptomes of the mutant including differential expression of vitellogenin genes. In addition, we found upregulation of the I am not dead yet (INDY) ortholog, which has been known to shorten the life span in Drosophila, explaining the shorter life span of the DNMT3.1 mutant. These results establish DNMT3.1 as a key regulator for life span and energy allocation between growth and reproduction during caloric restriction. Our findings reveal how energy allocation is implemented by selective expression of a DNMT3 ortholog that is widely distributed among animals. We also infer a previously unidentified adaptation of Daphnia that invests more energy for reproduction than growth under starved conditions.

Vitellogenin gene expression in marine mussels exposed to ethinylestradiol: No induction at the transcriptional level

Vitellogenin (Vtg), a large multidomain protein precursor of egg-yolk proteins, is used as an endocrine disruption biomarker in fish, and in the last decades, its use has been extended to invertebrates like mollusks. However, it remains unclear whether invertebrate endocrine system produces Vtg in response to estrogens, like it occurs in oviparous vertebrates. In a previous study, no evidence of induction of Vtg expression at protein level was found in gonads of the marine mussel Mytilus galloprovincialis after exposure to the estrogenic chemical 17α-ethinylestradiol (EE2). In the present follow-up study, it was investigated whether there is any effect of EE2 on Vtg abundance at transcriptional level in M. galloprovincialis gonads. To this aim, RT-qPCR analysis targeting three different domains of Vtg transcript was performed on gonads of mussels that were exposed either 4 or 24 days to 100 ng/L EE2. In addition, several reference genes were analysed and a selection of these for potential use in further RT-qPCR analyses on mussel male and female gonads is provided. Results showed higher expression in females than in males for the three analysed Vtg domains, and no evidence of Vtg mRNA induction due to EE2 either in females or males. The present results, together with those obtained from previous analysis at protein level, support that Vtg is not an adequate biomarker for xenoestrogenicity in marine mussels. Additionally, nucleotide sequences of Vtg transcripts of three closely-related species from Mytilus edulis complex (M. galloprovincialis, M. edulis and M. trossulus) are provided and compared with Vtg sequences from other mollusk species to assess the level of conservation and evolutionary relationships among species.

Molecular Characterization of the Von Willebrand Factor Type D Domain of Vitellogenin from Takifugu flavidus.

The von Willebrand factor type D (VWD) domain in vitellogenin has recently been found to bind tetrodotoxin. The way in which this protein domain associates with tetrodotoxin and participates in transporting tetrodotoxin in vivo remains unclear. A cDNA fragment of the vitellogenin gene containing the VWD domain from pufferfish (Takifugu flavidus) (TfVWD) was cloned. Using in silico structural and docking analyses of the predicted protein, we determined that key amino acids (namely, Val115, ASP116, Val117, and Lys122) in TfVWD mediate its binding to tetrodotoxin, which was supported by in vitro surface plasmon resonance analysis. Moreover, incubating recombinant rTfVWD together with tetrodotoxin attenuated its toxicity in vivo, further supporting protein–toxin binding and indicating associated toxicity-neutralizing effects. Finally, the expression profiling of TfVWD across different tissues and developmental stages indicated that its distribution patterns mirrored those of tetrodotoxin, suggesting that TfVWD may be involved in tetrodotoxin transport in pufferfish. For the first time, this study reveals the amino acids that mediate the binding of TfVWD to tetrodotoxin and provides a basis for further exploration of the molecular mechanisms underlying the enrichment and transfer of tetrodotoxin in pufferfish.

Effect of the Bacterium Paenibacillus larvae larvae on Vitellogenin Gene Expression of the Queen Honey Bee Apis mellifera L.

Virgin queens of the honey bee Apis mellifera L. were assessed following feeding in fourth larval instar with a sublethal dose of bacterium Paenibacillus larvae larvae (LD20 = 1.07 × 102 colony forming units (CFU)/queen), the causative agent of American foulbrood disease (AFB). The extraction of ovary proteins showed a highly significant increase for treated queens. The bacterium P. l. larvae was detected by conventional PCR-technique within treated queens ovaries with molecular size of 550 bp. Vitellogenin gene has been expressed in healthy and treated queens using RT-PCR technique, up-regulation took place in treated queens, vitellogenin was found with a high level of gene expression (∼20-fold). Finally, this study could contribute to initial efforts to help attempts to breed honey bee queens that are resistant to the pathogen.

Cloning, partial sequencing and 17β‐estradiol modulation of hepaticvitellogeningene of the Neotropical catfishRhamdia quelen

Expression of vitellogenin gene (vtg) is used as a biomarker for the evaluation of the exposure of estrogenic substances in fish. However, scientific information regarding this biomarker in Neotropical fish is limited. In this study, a 760 bp partial sequence of the vtg mRNA from the liver of the catfish Rhamdia quelen was cloned, representing almost 20% of the full-length vtg. The phylogenetic tree analysis recovered the vtg of R. quelen inside the clade of Siluriformes. The alignment of the deduced amino acid sequence of R. quelen vtg with other species confirmed that the described sequence is gene specific. Also, this cloned sequence presents almost 70% of identity with the vtgI subtype, that is known to translate into the incomplete form of Vtg due to the lack of the two domains, the β’-c and the Ct. Moreover, from the cloning and sequencing of vtg of R. quelen, a protocol for a RT-qPCR was developed with the goal to be applied as a biomarker of the hypothalamic-pituitary-gonad-liver (HPGL) axis, in order to evaluate the effects of endocrine disruptor exposure in Neotropical fish. Thus, this protocol was applied in the effects of a dose of 10 mg/kg of 17β-estradiol (E2) on vtg expression in male and female fish. The results showed that after 17 days of the exposure injection the E2 treatment upregulated vtg expression in both sexes. No observed differences in the levels of gene expression between the male and female fish were observed, and no statistical interaction between E2-treatment and sex were found. The results obtained from cloning add new information regarding vtg in Siluriformes fish, an order poorly studied in this aspect. Also, the vtg RT-qPCR protocol stablished for vtg of R. quelen will expand the application of this animal model, a Neotropical fish, in investigation regarding the effects of endocrine disruptors.

Assessment of the Effects of Double-Stranded RNAs Corresponding to Multiple Vitellogenesis-Inhibiting Hormone Subtype I Peptides in Subadult Female Whiteleg Shrimp, Litopenaeus vannamei.

Vitellogenesis-inhibiting hormone (VIH) negatively regulates reproduction in shrimp and other decapod crustaceans. In order to assess the effects of transcriptional silencing by multiple VIH subtype I sinus gland peptides (SGPs) on ovarian maturation in female whiteleg shrimp, Litopenaeus vannamei, we synthesized five dsRNAs targeting Liv-SGP-A, −B, −C, −F, and −G and injected them into subadults. The following treatments were employed: sgpG-dsRNA (targeting Liv-SGP-G), sgpC-dsRNA (targeting Liv-SGP-C), and mixed-dsRNA (targeting Liv-SGP-A, −B, and −F). The expression of Liv-SGP-G in eyestalks was significantly decreased at 10, 20, and 30 days after the injection of sgpG-dsRNA In addition, it was significantly decreased at 10 and 30 days after the injection of mixed-dsRNA. The expression of vitellogenin (Vg) gene expression in the ovaries, and concentrations of Vg protein in the hemolymph, were not changed by the administration of any dsRNA treatment (the ovaries remained immature in all treated individuals and contained mostly oogonia and previtellogenic oocytes). Although the administration of dsRNAs corresponding to multiple VIHs did not promote ovarian maturation, this is the first report of the co-transcriptional repression of Liv-SGP-G by the injection of dsRNA for homologous genes (Liv-SGP-A, −B, and −F). These results indicate that subadults can respond to the techniques of transcriptional silencing.

Sublethal effects of bistrifluron on key biological traits, macronutrients contents and vitellogenin (SeVg) expression in Spodoptera exigua (Hübner)

The beet armyworm, Spodoptera exigua, is a highly polyphagous pest originated from Southeast Asia but has spread globally, attacking economically important crops and fruits. Bistrifluron insecticide is one of the highly active insect growth regulators that has been reported to inhibit development and longevity in other lepidopteran species and could be used in the control of S. exigua. In the present study, the age-stage, two-sex life table technique was applied to assess the sublethal effects of bistrifluron on biological traits and vitellogenin gene (SeVg) expression when 2nd instar larvae fed to sublethal concentrations (LC10, LC20 and LC40) of bistrifluron. Mean generation time from eggs to adults was longer at LC40 (37.79 ± 0.81 d) and LC20 (37.04 ± 0.72) compared to the LC10 (36.89 ± 0.63 d) and control groups (36.07 ± 0.38 d). Fecundity of female at LC40 (279.17 ± 42.8 eggs), LC20 (347 ± 35.4 eggs) and LC10 (411.58 ± 42.38 eggs) were significantly lower than the control treatment (532.47 ± 7.13). Furthermore, the lower intrinsic rates of increase (LC40; r = 0.1207 ± 0.009, LC20; r = 0.1329 ± 0.009 and LC10; r = 0.14398 ± 0.009 compared to the control r = 0.164 ± 0.0076), was observed along with significantly extended mean generation times (LC40; T = 34.825 ± 0.317 days, LC20; T = 33.27 ± 0.368 days and LC10; T = 31.899 ± 0.398 days compared to the control 30.927 ± 0.255 days). Furthermore, the contents of energy reserve macronutrients (carbohydrate, lipid and protein) significantly reduced in dose and time dependent manner in treated insects as compared to control. Furthermore, the expression level of SeVg mRNA significantly decreased by 43.8% in the female adults when one-day-old second instar larvae were treated with sublethal concentrations of bistrifluron in comparison with the control. Documenting these sublethal effects is a vital, and often overlooked factor, in assessing the overall efficacy of insecticides in the management of pest populations.

Insulin-like androgenic gland hormone from the shrimp Fenneropenaeus merguiensis: Expression, gene organization and transcript variants.

Male sex differentiation in the crustacean is best known to be controlled by the insulin-like androgenic gland hormone (IAG). In this report, the cDNA and gene of the shrimp Fenneropenaeus merguiensis FmIAG were studied and characterized. FmIAG gene shares a high sequence identity in the coding region as well as the promoter region with that of F. chinensis. FmIAG gene is most likely consists of 5 exons and 4 introns. The cDNA reported here is the most abundant transcript that retained cryptic intron 4. The use of different splicing acceptor sites in exon 2 can produce a long-form FmIAG transcript variant with 6 additional amino acids inserted. Splicing of cryptic intron 4 would produce a transcript variant with a different C-terminal end. Therefore 4 different FmIAG transcripts can be produced from the FmIAG gene. During the molt cycle, the expression level of FmIAG was low in the early intermolt, increase steadily towards the late premolt and decreased rapidly in the early postmolt. In addition to the androgenic gland, FmIAG is also expressed in the hepatopancreas and ovary of adult females. Unilateral eyestalk ablation caused a significant increase in FmIAG transcript suggesting that the eyestalk consists of inhibiting factor(s) that suppressesFmIAGexpression. To explore the function of FmIAG in males, injection of FmIAG dsRNA knock-down the expression of FmIAG and up-regulated the expression of the vitellogenin gene in the testis and hepatopancreas. Interestingly a CHH-like gene identified in the androgenic gland was down-regulated. CHH-like gene knock-down resulted in altered expression of FmIAG in males suggesting that the CHH-like may be involved in FmIAG's regulation. RT-PCR with specific primers to the different transcript variant were used to determine if there is an association of different sizes of male and the type of IAG transcript. Results indicated that a high percentage of the large male shrimp expressed the long-form of FmIAG. The results suggested that FmIAG may be useful as a size marker for male shrimp aquaculture. In summary, the results of this study have expanded our knowledge of shrimp insulin-like androgenic gland hormone in male sex development and its potential role as a marker gene for growth regulation in shrimp.

Identification and Expression Characteristics of Vitellogenin Gene in Chrysopa pallens Males

Identification and Expression Characteristics of Vitellogenin Gene in Chrysopa pallens Males

RNAi-mediated silencing of vitellogenin gene curtails oogenesis in the almond moth Cadra cautella.

Vitellogenins, major yolk protein precursors, play an essential role in the reproduction and spread of all oviparous species, including insects. To investigate reproductive strategies of the warehouse moth Cadra cautella at the molecular level, a partial transcript of the C. cautella vitellogenin (CcVg) gene was extended through the rapid amplification of cDNA ends PCR and sequenced. The complete CcVg mRNA transcript was 5,334 bp long, which encoded a protein of 1,778 amino acids, including the first 14 amino acids of the signal peptide. The deduced CcVg protein contained a putative cleavage site (RTRR) at the amino-terminal side, similar to several other insect species. DGQR and GI/LCG motifs were present at the CcVg gene C-terminus, followed by nine cysteine residues. CcVg harbored 131 putative phosphorylation sites, numbering 84, 19, and 28 sites for serine, threonine, and tyrosine, respectively. The transcript showed a great resemblance with other lepidopteran Vgs. CcVg protein analysis revealed three conserved regions: 1) vitellogenin-N domain, 2) DUF 1943 (domain of unknown function), and 3) a von Willebrand factor type D domain. Additionally, sex, stage-specific, and developmental expression profiles of the CcVg gene were determined through RT-PCR. The Vg was first expressed in 22-day-old female larvae, and its expression increased with growth. The phylogenetic analysis based on different insect Vgs revealed that the CcVg exhibited close ancestry with lepidopterans. The CcVg-based RNAi experiments were performed, and the effects were critically evaluated. The qRT-PCR results showed that CcVg-based dsRNA suppressed the Vg gene expression up to 90% at 48 h post-injection. Moreover, CcVg-based RNAi effects resulted in low fecundity and egg hatchability in the CcVg-based dsRNA-treated females. The females laid eggs, but because of insufficient yolk protein availability the eggs could not succeed to hatch. The significant difference in the fecundity and hatchability unveils the importance of CcVg gene silencing and confirmed that the Vg gene plays a key role in C. cautella reproduction and it has the potential to be used as a target for RNAi-mediated control of this warehouse pest.

The presence of multiple copies of the vitellogenin gene in Fenneropenaeus merguiensis (De Man, 1888) (Decapoda: Dendrobranchiata: Penaeidae): Evidence for gene expansion and functional diversification in shrimps

Abstract Vitellogenin (Vg) is the precursor of egg yolk that provides nutrients to embryos of oviparous animals. We identified three Vg genes (FmVg1, FmVg2, and FmVg3) from the banana shrimp Fennerpenaeus merguiensis (De Man, 1888) (Penaeidae). The cDNAs ranged from 7,758 to 7,764 bp, and the encoded protein consisted of 2,553–2,585 amino acid residues. The genome structures of FmVg1, FmVg2, and FmVg3 were highly conserved, containing 15 exons and 14 introns. FmVg1-FmVg2, FmVg1-FmVg3, and FmVg2-FmVg3 shared a moderate 52.25%, 60.77%, and 56.45%, respectively. Phylogenetic analysis further revealed that the FmVg1 class vitellogenins are more conserved among the shrimps. The expression patterns of FmVg1, FmVg2, and FmVg3 were similar in the hepatopancreas at different ovarian developmental stages, whereas the expression trends between FmVg1 and FmVg2/3 in the ovary were remarkably different. During ontogenic development, the expression of these Vg genes all reached the highest levels at the post-larval stage. The three Vg genes also exhibited dynamic expression changes at different molting stages, with the highest expression level detected at the intermolt stage. Our study provides evidence that at least three copies of the Vg gene are present in the banana shrimp. These Vg genes are potentially involved in ovary maturation and larval development, and the divergence in their sequences, structures, and expression dynamics reflects their functional diversification in F. merguiensis. The expression of these Vg genes is therefore tightly regulated spatially and temporally. This is the first report for the molecular characterization of multiple vitellogenin genes in shrimps. Our results indicate that the vitellogenin gene is multi-functional and shows a non-sex specific expression pattern.

Tomato Chlorosis Virus Infection Facilitates Bemisia tabaci MED Reproduction by Elevating Vitellogenin Expression.

Simple SummaryThe sweet potato whitefly, Bemisia tabaci, is a polyphagous, global invasive insect pest. It can damage vegetables and crops directly by feeding and indirectly by transmitting plant viruses. Previously, we showed that virus infection of host plants can promote B. tabaci MED (Q biotype) reproduction. Here, using a whitefly-tomato chlorosis virus (ToCV)-tomato system, we investigated how ToCV modulates B. tabaci reproduction to facilitate its spread. ToCV infection significantly increased whitefly fecundity and the relative expression of vitellogenin gene (Vg). Both ovarian development and fecundity of whitefly were suppressed when Vg expression was silenced with or without ToCV infection. These combined results reveal that ToCV infection increases B. tabaci MED fecundity via elevated vitellogenin gene expression.Transmission of plant pathogenic viruses mostly relies on insect vectors. Plant virus could enhance its transmission by modulating the vector. Previously, we showed that feeding on virus infected plants can promote the reproduction of the sweet potato whitefly, Bemisia tabaci MED (Q biotype). In this study, using a whitefly-Tomato chlorosis virus (ToCV)-tomato system, we investigated how ToCV modulates B. tabaci MED reproduction to facilitate its spread. Here, we hypothesized that ToCV-infected tomato plants would increase B. tabaci MED fecundity via elevated vitellogenin (Vg) gene expression. As a result, fecundity and the relative expression of B. tabaci MED Vg was measured on ToCV-infected and uninfected tomato plants on days 4, 8, 12, 16, 20 and 24. The role of Vg on B. tabaci MED reproduction was examined in the presence and absence of ToCV using dietary RNAi. ToCV infection significantly increased B. tabaci MED fecundity on days 12, 16 and 20, and elevated Vg expression on days 8, 12 and 16. Both ovarian development and fecundity of B. tabaci MED were suppressed when Vg was silenced with or without ToCV infection. These combined results suggest that ToCV infection increases B. tabaci MED fecundity via elevated Vg expression.

Candidatus Liberibacter asiaticus manipulates the expression of vitellogenin, cytoskeleton, and endocytotic pathway-related genes to become circulative in its vector, Diaphorina citri (Hemiptera: Psyllidae)

The online version contains supplementary material available at 10.1007/s13205-021-02641-x.

Feasibility of Ripening Penaeus monodon by using Pheretima tschiliensis as a Bait and its Verification by Vitellogenin Gene Expression

Feasibility of Ripening Penaeus monodon by using Pheretima tschiliensis as a Bait and its Verification by Vitellogenin Gene Expression

Molecular cloning, characterisation and expression analysis of the vitellogenin genes vtgAo1 and vtgC during ovarian development in Chinese hook snout carp Opsariichthys bidens.

Vitellogenesis is essential for oocyte maturation. Vitellogenin (Vtg), a yolk precursor protein, plays an important role in oogenesis and vitellogenesis. Chinese hook snout carp Opsariichthys bidens is an economically important freshwater fish in China whose reproductive and developmental biology are not well understood. In this study, we undertook histological analysis to examine ovary development and oogenesis in O. bidens. The ovaries were divided into Stages II-V and oocytes were divided into perinuclear oocytes, cortical alveoli oocytes, vitellogenic oocytes and mature oocytes. Full-length cDNA sequences were cloned of two vtg genes from the liver of O. bidens, namely Ob-vtgAo1 and Ob-vtgC. Ob-vtgAo1 and Ob-vtgC cDNA are made up of 4136 and 4392 bases respectively and encode proteins containing 1335 and 1250 amino acids respectively. Ob-vtgAo1 contains three yolk protein domains: lipovitellin heavy chain (LvH), phosvitin (Pv) and lipovitellin light chain (LvL), whereas Ob-VtgC contains LvH and LvL, which are incomplete Vtgs. Ob-vtgAo1 and Ob-vtgC mRNA expression was significantly higher in the liver of O. bidens than in all other tissues. In oocytes of Stage II-III ovaries, yolk granules are almost absent and ovarian and hepatic Ob-vtgAo1 and Ob-vtgC expression is low. At Stage IV, the oocyte is filled with yolk granules and ovarian and hepatic Ob-vtgAo1 and Ob-vtgC expression is significantly increased. Collectively, these findings help us better understand vitellogenesis in O. bidens.

Reproductive performance and vitellogenin gene expression on female Bonylip barb (Osteochilus vittatus) during its reproductive cycle under culture conditions

Reproductive performance and vitellogenin gene expression on female Bonylip barb (Osteochilus vittatus) during its reproductive cycle under culture conditions

Investigation of Gene Sequence Divergence, Expression Dynamics, and Endocrine Regulation of the Vitellogenin Gene Family in the Whiteleg Shrimp Litopenaeus vannamei.

In this report, we studied the vitellogenin gene family in the whiteleg shrimp Litopenaeus vannamei by transcriptomics, bioinformatics, and molecular biology methods. At least three moderately homologous vitellogenin (Vg) genes (i.e. LvVg1, LvVg2, and LvVg3) were identified in the genome. The deduced LvVg proteins consisted of a vitellogenin_N domain, a DUF1943 domain, and a VWD domain typical of most vitellogenins from oviparous animals. LvVg1 was the most abundant Vg expressed in the hepatopancreas and ovary of maturing females. Furthermore, multiple isoforms of LvVg1 were evolved presumably due to the need for rapid Vg production during the rapid phase of vitellogenesis. LvVg transcripts were detected in different larval stages, juveniles, and subadults. During the non-reproductive cycle, LvVg expression in the hepatopancreas peaked at the intermolt stages. During the female vitellogenesis cycle, a two-phase expression pattern of LvVg1 gene was observed in the hepatopancreas and ovary. Moreover, the eyestalk optic nerve, brain, and thoracic ganglion consisted of factors that differentially regulated the expression of the three Vg genes. In addition to their reproduction-related roles, Vg may also be involved in growth and molt-related processes. Phylogenetic analysis revealed the early expansion and separation of these Vg genes, and it is most likely correlated with the expansion of Vg’s function. In conclusion, the evolution of multiple LvVg1 isoforms and the acquisition of different Vg genes (i.e. LvVg2 and LvVg3) may occur universally in most decapods. Full information on the total number of Vg genes and precise knowledge on the expression pattern and endocrine regulation of each Vg during all life cycle stages are crucial for us to understand the roles of this emerging gene family in the control of shrimp reproduction and other non-reproductive processes.

Expressions of conventional vitellogenin and vitellogenin-like A in worker brains are associated with a nursing task in a ponerine ant.

In eusocial insect colonies, non-reproductive workers often perform different tasks. Tasks of an individual worker are shifted depending on various factors, e.g., age and colony demography. Although a vitellogenin (Vg) gene play regulatory roles in both reproductive and non-reproductive division of labours in a honeybee, it has been shown that the insect Vg underwent multiple gene duplications and sub-functionalisation, especially in apical ant lineages. The regulatory roles of duplicated Vgs were suggested to change evolutionarily among ants, whereas such roles in phylogenetically basal ants remain unclear. Here, we examined the expression patterns of conventional Vg (CVg), Vg-like A, Vg-like B and Vg-like C, as well as Vg receptor, during the task shift in an age-dependent manner and under experimental manipulation of colony demography in a primitive ant Diacamma sp. Expressions of CVg and Vg-like A in a brain were associated with a nursing task. It is suggested that associations of brain expressions of these Vgs with worker tasks were acquired in the basal ant lineage, and that such Vg functions could have sub-functionalised in the derived ant lineage.