Update of the Gene Discovery Program in Schistosoma mansoni with the Expressed Sequence Tag Approach

Abstract

Continuing theThe study of the Schistosoma mansoni genome has a high priority in the effort to understand the multiple facets of this complex parasite. Accordingly, a S. mansoni genome project was started in 1992 as a Brazilian initiative. From the original cDNA library used, 607 ESTs were generated (Franco et al. 1995a,b) leading to the identification of 154 new genes. This increased considerably the number of known genes in S. mansoni.The S. mansoni genome project was adopted by the World Health Organization (WHO) and has been partially funded by this institution in a collaborative international project with the aim of undertaking a co-ordinated gene discovery program in S. mansoni. We wish to report the sequencing of 363 further templates by our laboratory, with identification of 91 genes, 74 of which have not been previously described in S. mansoni. MATERIALS AND METHODSPlasmidial DNA preparation, sequencing and analysis of the sequences were done essentially as described by Franco et al. (1995a). RESULTSTables I an II summarise the data found in the 363 templates sequenced, which produced 205 useful ESTs derived from 185 clones. Some clones were sequenced in both directions using the forward and reverse primers and thus producing two ESTs for the same gene. ESTs for 185 clones. All sequences were submitted to homology searches in DNA and protein databanks showing that the 205 ESTs corresponded to 91 different genes, 81% of which had not been previously described in the parasite. The sequences were grouped according to the following criteria: sequences presenting homology to previous identified S. mansoni genes (Tables II and III), sequences identified by homology with other organisms (Tables II and IV) and sequences with no homology with any gene deposited in database banks (Table II). Sequences showing low homology with other organisms were identified as partial matches (Tables II and V).

Ontogeny of a synaptophysin-mediated GABA transmission mechanism from the ciliary band-associated strand to the ciliary band during the development of the sea urchin Hemicentrotus pulcherrimus

“…The CBAS contains numerous Syp-immunoreactive puncta (Katow et al, 2016), suggesting neurosecretory activity of the organ. In addition to the sea urchin, Syp has been reported in vast phylogenetic groups of invertebrates, such as the flatworm (Schistosoma mansoni; Rabelo et al, 1997), C. elegans (Abraham et al, 2011), insects (Calábria, et al, 2011;Stevens et al, 2012), Aplysia (Jin et al, 2011) and Octopus (Zhang et al, 2012).…”

Characterization of constitutive and putative differentially expressed mRNAs by means of expressed sequence tags, differential display reverse transcriptase-PCR and randomly amplified polymorphic DNA-PCR from the sand fly vector Lutzomyia longipalpis

“…The characterization of promoters and genes can be achieved through the identification of expressed sequenced tags (EST). EST analysis has been used to understand molecular aspects of a given organism (e.g., P. falciparum, Chakrabarti et al 1994) or to help in a gene discovery/genome mapping program (e.g., Schistosoma mansoni, Rabelo et al 1997).…”

Efeitos do pareamento no perfil de expressão gênica do parasita Schistosoma mansoni

“…Em 2000, a primeira biblioteca genômica de Schistosoma foi construída em vetor BAC, a seqüências das extremidades dos insertos de 93 clones foi determinada, e a biblioteca com mais de 21 mil clones foi imobilizada em membranas de nylon e usada para experimentos de hibridização (Le Paslier et al, 2000). Até 2003 haviam sido obtidas 16.813 seqüências de fragmentos de genes expressos (ESTs), um esforço de alguns grupos no mundo, incluindo um consórcio internacional financiado pela OMS (Franco et al, 1995;Machado-Silva et al, 1995;Franco et al, 1997;Rabelo et al, 1997;Santos et al, 1999;Merrick et al, 2003). Almeida et al, 2003).…”