Nimbus (BgI): An active non-LTR retrotransposon of the Schistosoma mansoni snail host Biomphalaria glabrata

Raghavan, Nithyakalyani; Tettelin, Hervé; Miller, André; Hostetler, Jessica B.; Tallon, Luke J.; Knight, Matty

doi:10.1016/j.ijpara.2007.04.002

Cited by 20 publications

(27 citation statements)

References 53 publications

(74 reference statements)

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“…To determine whether the kinetics of nimbus RT induction coincides with that of Hsp 70 following exposure to either normal or attenuated miracidia, we examined the expression of the nimbus RT transcript (Raghavan, et al, 2003, Raghavan, et al, 2007) in the RNA samples described above. Susceptible snails exposed 5 hours to normal miracidia showed a significant increase (28.9 fold) in nimbus RT with a steady decrease (26.51 to 12.49 fold) in the levels of expression between 10 to 48 hours post-exposure (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…To resolve this uncertainty regarding the differential gene expression of Hsp 70 between resistant and susceptible snails, especially during early time points when subjected to stress from heat shock (abiotic stress) and following parasite (biotic stress) infection, we decided to further examine the differential Hsp 70 induction in parasite resistant vs susceptible juvenile snails before and after either heat shock or infection. In addition, modulation of the reverse transcriptase (RT) encoding domain of the snail non-LTR retrotransposon, nimbus , in relation to stress (heat shock and infection) was also investigated (Raghavan, et al, 2003, Raghavan, et al, 2007). Mobile genetic elements (MGEs), such as non-LTR-retrotransposons have been shown to be activated by pathogens, environmental stress, and wounding (Mhiri, et al, 1997, Wessler, 1996).…”

Section: Introductionmentioning

confidence: 99%

“…This induction was dramatic in the susceptible juvenile snail and occurred early post exposure and coincidentally, within the same time period with elevated expression of the RT of the non-LTR-retrotransposon, nimbus (Raghavan, et al, 2007). In contrast, inductions of both loci were less pronounced and occurred following a longer lag time (post exposure) in resistant and non-susceptible snails exposed to normal miracidia, and was absent in all snail strains following exposure to attenuated miracidia.…”

Section: Introductionmentioning

confidence: 99%

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Schistosoma mansoni infection of juvenile Biomphalaria glabrata induces a differential stress response between resistant and susceptible snails

Ittiprasert

Nene

Miller

et al. 2009

Experimental Parasitology

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Schistosomes develop successfully in susceptible snails but are encapsulated and killed in resistant ones. Mechanism(s) shaping these outcomes involves the parasites ability to evade the snail's defenses. RNA analysis from resistant (BS-90), non-susceptible (LAC2) and susceptible (NMRI) juvenile Biomphalaria glabrata to Schistosoma mansoni revealed that stress related genes, heat shock protein 70 (Hsp 70) and reverse transcriptase (RT), were dramatically co-induced early in susceptible snails, but not in resistant/non-susceptible ones. These transcripts were, however, down regulated upon exposure to irradiated parasites although penetration behavior of irradiated vs normal parasites were the same, indicating that Hsp 70 regulation was elicited by infection and not injury. Understanding molecular events involved in stress response transcriptional regulation of Hsp 70 in juvenile snails could pave a way towards the identification of genes involved in schistosome/snail interactions.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Schistosoma mansoni infection of juvenile Biomphalaria glabrata induces a differential stress response between resistant and susceptible snails

Ittiprasert

Nene

Miller

et al. 2009

Experimental Parasitology

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“…However, currently available data in the public domain for the B. glabrata genome shows that aside from its inherent repetitive nature it also contains different types of mobile genetic elements. We previously characterised one of these elements, the non-long terminal repeat (LTR) retrotransposon, nimbus (Raghavan et al, 2007), and have since shown that the reverse transcriptase (RT) domain of this element is co-transcribed with the stress gene, Hsp 70, early in susceptible juvenile snails (NMRI and M-line) after S. mansoni infection (Ittiprasert et al, 2009). …”

Section: Resultsmentioning

confidence: 99%

Identification and characterisation of functional expressed sequence tags-derived simple sequence repeat (eSSR) markers for genetic linkage mapping of Schistosoma mansoni juvenile resistance and susceptibility loci in Biomphalaria glabrata

Ittiprasert

Miller

et al. 2013

International Journal for Parasitology

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Biomphalaria glabrata susceptibility to Schistosoma mansoni has a strong genetic component, offering the possibility for investigating host–parasite interactions at the molecular level, perhaps leading to novel control approaches. The identification, mapping and molecular characterisation of genes that influence the outcome of parasitic infection in the intermediate snail host is, therefore, seen as fundamental to the control of schistosomiasis. To better understand the evolutionary processes driving disease resistance/susceptibility phenotypes, we previously identified polymorphic random amplification of polymorphic DNA and genomic simple sequence repeats from B. glabrata. In the present study we identified and characterised polymorphic expressed simple sequence repeats markers (Bg-eSSR) from existing B. glabrata expressed sequence tags. Using these markers, and with previously identified genomic simple sequence repeats, genetic linkage mapping for parasite refractory and susceptibility phenotypes, the first known for B. glabrata, was initiated. Data mining of 54,309 expressed sequence tag, produced 660 expressed simple sequence repeats of which dinucleotide motifs (TA)n were the most common (37.88%), followed by trinucleotide (29.55%), mononucleotide (18.64%) and tetranucleotide (10.15%). Penta- and hexanucleotide motifs represented <3% of the Bg-eSSRs identified. While the majority (71%) of Bg-eSSRs were monomorphic between resistant and susceptible snails, several were, however, useful for the construction of a genetic linkage map based on their inheritance in segregating F2 progeny snails derived from crossing juvenile BS-90 and NMRI snails. Polymorphic Bg-eSSRs assorted into six linkage groups at a logarithm of odds score of 3. Interestingly, the heritability of four markers (Prim1_910, Prim1_771, Prim6_1024 and Prim7_823) with juvenile snail resistance were, by t-test, significant (P < 0.05) while an allelic marker, Prim24_524, showed linkage with the juvenile snail susceptibility phenotype. On the basis of our results it is possible that the gene(s) controlling juvenile resistance and susceptibility to S. mansoni infection in B. glabrata are not only on the same linkage group but lie within a short distance (42 cM) of each other.

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“…To better qualify for full genome sequencing, some research communities developed complementary genomic resources. Bacterial artificial chromosome (BAC) libraries were developed for several molluscs like B. glabrata (Gastropda) and the oysters Crassostrea virginica and C. gigas , to gain initial access to genomic information (Adema et al, 2006; Cunningham et al, 2006; Raghavan et al, 2007). BAC libraries consist of considerable numbers of clones that represent the full genome with large (>100kb) inserts of molluscan genomic DNA.…”

Section: Genomes and Next-generation Sequencing Immunogenomics Phmentioning

confidence: 99%

Comparative immunogenomics of molluscs

Schultz

Adema

2017

Developmental & Comparative Immunology

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Comparative immunology, studying both vertebrates and invertebrates, provided the earliest descriptions of phagocytosis as a general immune mechanism. However, the large scale of animal diversity challenges all-inclusive investigations and the field of immunology has developed by mostly emphasizing study of a few vertebrate species. In addressing the lack of comprehensive understanding of animal immunity, especially that of invertebrates, comparative immunology helps toward management of invertebrates that are food sources, agricultural pests, pathogens, or transmit diseases, and helps interpret the evolution of animal immunity. Initial studies showed that the Mollusca (second largest animal phylum), and invertebrates in general, possess innate defenses but lack the lymphocytic immune system that characterizes vertebrate immunology. Recognizing the reality of both common and taxon-specific immune features, and applying up-to-date cell and molecular research capabilities, in-depth studies of a select number of bivalve and gastropod species continue to reveal novel aspects of molluscan immunity. The genomics era heralded a new stage of comparative immunology; large-scale efforts yielded an initial set of full molluscan genome sequences that is available for analyses of full complements of immune genes and regulatory sequences. Next-generation sequencing (NGS), due to lower cost and effort required, allows individual researchers to generate large sequence datasets for growing numbers of molluscs. RNAseq provides expression profiles that enable discovery of immune genes and genome sequences, reveal distribution and diversity of immune factors across molluscan phylogeny. Although computational de novo sequence assembly will benefit from continued development and automated annotation may require some experimental validation, NGS is a powerful tool for comparative immunology, especially increasing coverage of the extensive molluscan diversity. To date, immunogenomics revealed new levels of complexity of molluscan defense by indicating sequence heterogeneity in individual snails and bivalves, and members of expanded immune gene families are expressed differentially to generate pathogen-specific defense responses.

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Nimbus (BgI): An active non-LTR retrotransposon of the Schistosoma mansoni snail host Biomphalaria glabrata

Cited by 20 publications

References 53 publications

Schistosoma mansoni infection of juvenile Biomphalaria glabrata induces a differential stress response between resistant and susceptible snails

Schistosoma mansoni infection of juvenile Biomphalaria glabrata induces a differential stress response between resistant and susceptible snails

Identification and characterisation of functional expressed sequence tags-derived simple sequence repeat (eSSR) markers for genetic linkage mapping of Schistosoma mansoni juvenile resistance and susceptibility loci in Biomphalaria glabrata

Comparative immunogenomics of molluscs

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