Developmental Switching in the Parasitic Nematode Strongyloides stercoralis Is Controlled by the ASF and ASI Amphidial Neurons

Ashton, F.; Bhopale, Veena M.; Holt, Douglas; Smith, Gary; Schad, Gerhard A.

doi:10.2307/3284571

Cited by 61 publications

(50 citation statements)

References 19 publications

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“…C. elegans gpa-3 is expressed in eight pairs of chemosensory neurons in the amphidial complex (ADF, ADL, ASE, ASG, ASH, ASI, ASJ and ASK), two pairs of sensory neurons in the phasmids (PHA and PHB) and two other non-sensory cells (Jansen, et al, 1999). The amphidial neurons of S. stercoralis have been described and their homologies with amphidial neurons of C. elegans have been proposed based on morphology, position of cell bodies within the lateral ganglion and, in several cases, function inferred from microlaser ablation studies (Ashton, et al, 1995;Ashton, et al, 1998;Lopez, et al, 2000;Nolan, et al, 2004;Ashton, et al, 2007). We have not yet determined the specific identities of the GFP-expressing neurons in S. stercoralis transformed with pAJ09.…”

Section: Discussionmentioning

confidence: 99%

Strongyloides stercoralis: Cell- and tissue-specific transgene expression and co-transformation with vector constructs incorporating a common multifunctional 3′ UTR

Junio

Massey

et al. 2008

Experimental Parasitology

116

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Transgenesis is a valuable methodology for studying gene expression patterns and gene function. It has recently become available for research on some parasitic nematodes, including Strongyloides stercoralis. Previously, we described a vector construct, comprising the promoter and 3′ UTR of the S. stercoralis gene Ss era-1 that gives expression of GFP in intestinal cells of developing F1 progeny. In the present study, we identified three new S. stercoralis promoters, which, in combination with the Ss era-1 3′ UTR, can drive expression of GFP or the red fluorescent protein, mRFPmars, in tissuespecific fashion. These include Ss act-2, which drives expression in body wall muscle cells, Ss gpa-3, which drives expression in amphidial and phasmidial neurons and Ss rps-21, which drives ubiquitous expression in F1 transformants and in the gonads of microinjected P0 female worms. Concomitant microinjection of vectors containing GFP and mRFPmars gave dually transformed F1 progeny, suggesting that these constructs could be used as co-injection markers for other transgenes of interest. We have developed a vector "toolkit" for S. stercoralis including constructs with the Ss era-1 3′ UTR and each of the promoters described above.

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Section: Discussionmentioning

confidence: 99%

Strongyloides stercoralis: Cell- and tissue-specific transgene expression and co-transformation with vector constructs incorporating a common multifunctional 3′ UTR

Junio

Massey

et al. 2008

Experimental Parasitology

116

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“…In S. stercoralis the switch between alternative female morphs requires the presence of two amphidial (paired anterior sensory structures) neurons in the ¢rst-stage larval progeny of parasitic females (Ashton et al 1998). Larvae in which two pairs of amphidial neurons (ASF and ASI) were ablated with a laser microbeam developed into directly developing iL3s, whereas untreated larvae or larvae in which only ASF or ASI was ablated developed into freeliving females.…”

Section: Discussionmentioning

confidence: 99%

The control of morph development in the parasitic nematodeStrongyloides ratti

Harvey

Gemmill

Read

et al. 2000

Proc. R. Soc. Lond. B

115

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The parasitic nematode Strongyloides ratti has a complex life cycle. The progeny of the parasitic females can develop into three distinct morphs, namely directly developing infective third-stage larvae (iL3s), free-living adult males and free-living adult females. We have analysed of the e¡ect of host immune status (an intra-host factor), environmental temperature (an extra-host factor) and their interaction on the proportion of larvae that develop into these three morphs. The results are consistent with the developmental decision of larvae being controlled by at least two discrete developmental switches. One is a sexdetermination event that is a¡ected by host immune status and the other is a switch between alternative female morphs that is a¡ected by both host immune status and environmental temperature. These ¢nd-ings clarify the basis of the life cycle of S. ratti and demonstrate how such complex life cycles can result from a combination of simple developmental switches.

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“…Parasitic females in the intestine produce eggs by mitotic parthenogenesis, and first-stage (L1) larvae are excreted in stool. Larvae use environmental and genetic cues to determine their developmental path, becoming free-living adults (heterogonic pathway) or third-stage infective (L3i) larvae (homogonic pathway ;Schad 1990;Ashton et al 1998;Grant and Viney 2001). S. stercoralis free-living worms can complete one life cycle of sexual reproduction outside the host, generating progeny that must re-enter parasitic development (Yamada et al 1991).…”

Section: Strongyloides Pathogenesis and Biologymentioning

confidence: 99%

Comparative Genomics of Gene Expression in the Parasitic and Free-Living Nematodes Strongyloides stercoralis and Caenorhabditis elegans

Mitreva¹,

McCarter²,

Martin³

et al. 2004

Genome Res.

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Although developmental timing of gene expression is used to infer potential gene function, studies have yet to correlate this information between species. We analyzed 10,921 ESTs in 3311 clusters from first-and infective third-stage larva (L1, L3i) of the parasitic nematode Strongyloides stercoralis and compared the results to Caenorhabditis elegans, a species that has an L3i-like dauer stage. In the comparison of S. stercoralis clusters with stage-specific expression to C. elegans homologs expressed in either dauer or nondauer stages, matches between S. stercoralis L1 and C. elegans nondauer-expressed genes dominated, suggesting conservation in the repertoire of genes expressed during growth in nutrient-rich conditions. For example, S. stercoralis collagen transcripts were abundant in L1 but not L3i, a pattern consistent with C. elegans collagens. Although a greater proportion of S. stercoralis L3i than L1 genes have homologs among the C. elegans dauer-specific transcripts, we did not uncover evidence of a robust conserved L3i/dauer 'expression signature.' Strikingly, in comparisons of S. stercoralis clusters to C. elegans homologs with RNAi knockouts, those with significant L1-specific expression were more than twice as likely as L3i-specific clusters to match genes with phenotypes. We also provide functional classifications of S. stercoralis clusters.

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Developmental Switching in the Parasitic Nematode Strongyloides stercoralis Is Controlled by the ASF and ASI Amphidial Neurons

Cited by 61 publications

References 19 publications

Strongyloides stercoralis: Cell- and tissue-specific transgene expression and co-transformation with vector constructs incorporating a common multifunctional 3′ UTR

Strongyloides stercoralis: Cell- and tissue-specific transgene expression and co-transformation with vector constructs incorporating a common multifunctional 3′ UTR

The control of morph development in the parasitic nematodeStrongyloides ratti

Comparative Genomics of Gene Expression in the Parasitic and Free-Living Nematodes Strongyloides stercoralis and Caenorhabditis elegans

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