Eyestalk Ablation Has Little Effect on Actin and Myosin Heavy Chain Gene Expression in Adult Lobster Skeletal Muscles

Medler, Scott; Brown, Kitty; Chang, Ernest S.; Mykles, Donald L.

doi:10.2307/3593121

Cited by 14 publications

(19 citation statements)

References 53 publications

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“…We did observe a trend toward greater actin expression in shallow samples and would recommend caution in normalizing C. finmarchicus gene expression to actin. During the molt cycle, crustacean muscles undergo cycles of atrophy and remodeling, and actin gene expression can vary by developmental stage and molt phase (Medler et al 2005, de Oliveira Cesar et al 2006, Sellars et al 2007). Given the changes in structure and metabolism associated with diapause and molting, it is not clear that normalization to expression of a single nuclear gene would be appropriate in studies of gene expression associated with diapause state.…”

Section: Evaluation Of Housekeeping Genesmentioning

confidence: 99%

Differential gene expression in diapausing and active Calanus finmarchicus (Copepoda)

Tarrant¹,

Baumgartner²,

Verslycke³

et al. 2008

Mar. Ecol. Prog. Ser.

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To survive long periods of low food availability, some calanoid copepods have a life history that includes a diapause phase during which copepodids delay development to adulthood, migrate to depth, reduce metabolism, and utilize stored lipids for nourishment. While seasonal patterns in diapause have been described, the environmental and physiological regulation of diapause has not been elucidated. We collected Calanus finmarchicus C5 copepodids from surface (0 to 39 m) and deep (157 to 201 m) waters in the Gulf of Maine, and both morphological and biochemical measurements indicated that these copepodids were from active and diapausing populations, respectively. Two complementary molecular techniques were used to compare gene expression in these 2 groups: (1) suppressive subtractive hybridization (SSH) was used to identify genes that may be differentially expressed, and (2) quantitative real-time RT-PCR was used to characterize patterns of gene expression in individual copepodids. Three genes associated with lipid synthesis, transport and storage (ELOV, FABP, RDH) were upregulated (more highly expressed) in active copepods, particularly those with small oil sacs. Expression of ferritin was greater in diapausing copepods with large oil sacs, consistent with a role of ferritin in chelating metals to protect cells from oxidative stress and/or delay development. Ecdysteroid receptor (EcR) expression was greater in diapausing copepods, highlighting the need for further investigation into endocrine regulation of copepod development. This study represents the first molecular characterization of gene expression associated with calanoid copepod diapause and provides a foundation for future investigations of the underlying mechanisms that regulate diapause. 355: 193-207, 2008 result of this build-up of lipids, copepods with this life history strategy are an extremely nutritious food source for their predators. Thus, the environmental and physiological factors that control development and, in particular, diapause, have important implications for marine ecosystem processes. KEY WORDS: Diapause · Copepod · Calanus finmarchicus · Subtractive hybridization · Gene expression · Gulf of Maine Resale or republication not permitted without written consent of the publisherMar Ecol Prog SerThe environmental signals and internal biological processes that regulate diapause in calanoid copepods are unknown, and experimental studies remain difficult because copepods do not reliably enter diapause in the laboratory. In the field, investigators have relied on a suite of behavioral, morphological, and biochemical characteristics to distinguish between diapausing and active copepodids. The hallmarks of diapause are a deep distribution (within 50 to 100 m of the bottom in neritic environments and below 200 to 300 m in oceanic waters (Sameoto & Herman 1990, Miller et al. 1991, Dale et al. 1999, Heath et al. 2004), predominance of a single stage (Heath et al. 2004), torpor (Hirche 1983), empty guts with reduced epithelium (Hallberg ...

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Section: Evaluation Of Housekeeping Genesmentioning

confidence: 99%

Differential gene expression in diapausing and active Calanus finmarchicus (Copepoda)

Tarrant¹,

Baumgartner²,

Verslycke³

et al. 2008

Mar. Ecol. Prog. Ser.

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“…Animals were anesthetized with ice for 5 min prior to dissection of the YO and other tissues. Hemolymph samples (100 μl) were combined with 300 μl methanol for quantification of ecdysteroids by radioimmunoassay (Medler et al, 2005) or ELISA (see Appendix). Tissues were frozen in liquid nitrogen and stored at −80°C.…”

Section: Rna Isolation and Mrna Analysismentioning

confidence: 99%

Molt regulation in green and red color morphs of the crab,Carcinus maenas: gene expression of molt-inhibiting hormone signaling components

Abuhagr

Blindert

Nimitkul

et al. 2013

Journal of Experimental Biology

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There was an error published in J. Exp. Biol. 217, In Fig. 3, the letters and numbers indicating which means were significantly different are missing from panel A. The correct figure is printed below.We apologise to the authors and readers for this omission. ) characteristic of late premolt animals and animals did not molt by 90 days post-ESA. There was no effect of ESA or MLA on the expression of Cm-elongation factor 2 (EF2), Cm-NOS, the beta subunit of GC-I (Cm-GC-Iβ), a membrane receptor GC (Cm-GC-II) and a soluble NO-insensitive GC (Cm-GC-III) in green morphs. Red morphs were affected by prolonged ESA and MLA treatments, as indicated by large decreases in Cm-EF2, Cm-GC-II and Cm-GC-III mRNA levels. ESA accelerated the transition of green morphs to the red phenotype in intermolt animals. ESA delayed molting in premolt green morphs, whereas intact and MLA animals molted by 30 days post treatment. There were significant effects on YO gene expression in intact animals: Cm-GC-Iβ mRNA increased during premolt and Cm-GC-III mRNA decreased during premolt and increased during postmolt. Cm-MIH transcripts were detected in eyestalk ganglia, the brain and the thoracic ganglion from green intermolt animals, suggesing that MIH in the brain and thoracic ganglion prevents molt induction in green ESA animals.

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“…Elevated ecdysteroid levels have little effect on actin and myosin heavy chain mRNA levels (El Haj, 1999;Medler et al, 2005;Whiteley and El Haj, 1997). Increased protein synthesis during premolt is correlated with increased ribosomal activity (El Haj et al, 1996;Skinner, 1965;Skinner, 1968).…”

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confidence: 99%

Rheb, an activator of target of rapamycin, in the blackback land crab,Gecarcinus lateralis: cloning and effects of molting and unweighting on expression in skeletal muscle

MacLea

Abuhagr

Pitts

et al. 2012

Journal of Experimental Biology

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SUMMARY Molt-induced claw muscle atrophy in decapod crustaceans facilitates exuviation and is coordinated by ecdysteroid hormones. There is a 4-fold reduction in mass accompanied by remodeling of the contractile apparatus, which is associated with an 11-fold increase in myofibrillar protein synthesis by the end of the premolt period. Loss of a walking limb or claw causes a loss of mass in the associated thoracic musculature; this unweighting atrophy occurs in intermolt and is ecdysteroid independent. Myostatin (Mstn) is a negative regulator of muscle growth in mammals; it suppresses protein synthesis, in part, by inhibiting the insulin/metazoan target of rapamycin (mTOR) signaling pathway. Signaling via mTOR activates translation by phosphorylating ribosomal S6 kinase (s6k) and 4E-binding protein 1. Rheb (Ras homolog enriched in brain), a GTP-binding protein, is a key activator of mTOR and is inhibited by Rheb-GTPase-activating protein (GAP). Akt protein kinase inactivates Rheb-GAP, thus slowing Rheb-GTPase activity and maintaining mTOR in the active state. We hypothesized that the large increase in global protein synthesis in claw muscle was due to regulation of mTOR activity by ecdysteroids, caused either directly or indirectly via Mstn. In the blackback land crab, Gecarcinus lateralis, a Mstn-like gene (Gl-Mstn) is downregulated as much as 17-fold in claw muscle during premolt and upregulated 3-fold in unweighted thoracic muscle during intermolt. Gl-Mstn expression in claw muscle is negatively correlated with hemolymph ecdysteroid level. Full-length cDNAs encoding Rheb orthologs from three crustacean species (G. lateralis, Carcinus maenas and Homarus americanus), as well as partial cDNAs encoding Akt (Gl-Akt), mTOR (Gl-mTOR) and s6k (Gl-s6k) from G. lateralis, were cloned. The effects of molting on insulin/mTOR signaling components were quantified in claw closer, weighted thoracic and unweighted thoracic muscles using quantitative polymerase chain reaction. Gl-Rheb mRNA levels increased 3.4-fold and 3.9-fold during premolt in claw muscles from animals induced to molt by eyestalk ablation (ESA) and multiple leg autotomy (MLA), respectively, and mRNA levels were positively correlated with hemolymph ecdysteroids. There was little or no effect of molting on Gl-Rheb expression in weighted thoracic muscle and no correlation of Gl-Rheb mRNA with ecdysteroid titer. There were significant changes in Gl-Akt, Gl-mTOR and Gl-s6k expression with molt stage. These changes were transient and were not correlated with hemolymph ecdysteroids. The two muscles differed in terms of the relationship between Gl-Rheb and Gl-Mstn expression. In thoracic muscle, Gl-Rheb mRNA was positively correlated with Gl-Mstn mRNA in both ESA and MLA animals. By contrast, Gl-Rheb mRNA in claw muscle was negatively correlated with Gl-Mstn mRNA in ESA animals, and no correlation was observed in MLA animals. Unweighting increased Gl-Rheb expression in thoracic muscle at all molt stages; the greatest difference (2.2-fold) was observed in intermolt animals. There was also a 1.3-fold increase in Gl-s6k mRNA level in unweighted thoracic muscle. These data indicate that the mTOR pathway is upregulated in atrophic muscles. Gl-Rheb, in particular, appears to play a role in the molt-induced increase in protein synthesis in the claw muscle.

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Eyestalk Ablation Has Little Effect on Actin and Myosin Heavy Chain Gene Expression in Adult Lobster Skeletal Muscles

Cited by 14 publications

References 53 publications

Differential gene expression in diapausing and active Calanus finmarchicus (Copepoda)

Differential gene expression in diapausing and active Calanus finmarchicus (Copepoda)

Molt regulation in green and red color morphs of the crab,Carcinus maenas: gene expression of molt-inhibiting hormone signaling components

Rheb, an activator of target of rapamycin, in the blackback land crab,Gecarcinus lateralis: cloning and effects of molting and unweighting on expression in skeletal muscle

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