Developmental pattern of telomerase expression in the sand scallop, Euvola ziczac

Abstract

Abstract. Telomerase is a ribonucleoprotein that can maintain telomeres, the repetitive sequences of DNA found at the end of eukaryotic chromosomes, and confer long‐term proliferative capacity on cells. Telomerase expression is essential during periods of intense cell division such as the early developmental process. In later development, some species retain telomerase activity while others repress telomerase activity in what is thought to be a tumor‐protective mechanism. Despite the importance of telomerase expression in both development and neoplastic disease, no studies to date have characterized its expression in bivalves. We present the first report of telomerase expression in a bivalve species, the sand scallop, Euvola ziczac. Telomerase activity was detected throughout the early stages of development and in all adult tissues examined. Analysis of DNA isolated from adult tissues indicated long telomeres, with terminal restriction fragment lengths >20 kb in both somatic and germ tissues. Ubiquitous telomerase expression throughout development and into adulthood would suggest a lack of telomere‐related senescence and suggests that these scallops do not use telomerase repression as a mechanism to suppress the formation of neoplasm.

Telomere-independent ageing in the longest-lived non-colonial animal, Arctica islandica

“…Due to the chosen sampling pattern we have no information about telomere length during earlier growth stages of individuals younger than 6 years from the IC, 10 years from the BS and 11 years from the IS population. Telomerase expression of the sand scallop, Euvola ziczac, however has been detected in adult tissue (adductor muscle, gill, mantle, and male and female gonads) as well as during early developmental stages (Owen et al, 2007). The results of A. islandica are in line with other animals showing indeterminate growth, such as the rainbow trout, lobsters, molluscs, or other marine invertebrates, which express telomerase in all examined tissues during their complete investigated lifespan (Klapper et al, 1998b;Owen et al, 2007).…”

“…Telomerase expression of the sand scallop, Euvola ziczac, however has been detected in adult tissue (adductor muscle, gill, mantle, and male and female gonads) as well as during early developmental stages (Owen et al, 2007). The results of A. islandica are in line with other animals showing indeterminate growth, such as the rainbow trout, lobsters, molluscs, or other marine invertebrates, which express telomerase in all examined tissues during their complete investigated lifespan (Klapper et al, 1998b;Owen et al, 2007). As an emerging model system for ageing studies, bivalves, and especially the ocean quahog, can also compete with established longlived model systems for ageing such as primates and the naked molerat (Austad, 2010;Fischer and Steven, 2011;Lewis et al, 2012) that show similar life history associations between MLSP and growth rate or development (i.e.…”

“…This applies to most fish, lobsters, molluscs, and other long-lived marine invertebrates (e.g. Estabrooks, 2007;Klapper et al, 1998a;Klapper et al, 1998b;Owen et al, 2007;Plohl et al, 2002;Sköld et al, 2011).…”

Impaired telomerase activity hinders proliferation and in vitro transformation of Penaeus monodon lymphoid cells

“…The need for telomerase activity may be explained from the active cell proliferation required in various stages of its life cycle for attaining growth including regeneration of exoskeleton during molting, suggesting maintenance of stem cellness throughout life . Such constitutive activity of telomerase has been reported from lobsters (Klapper et al 1998a), bivalves (Owen et al 2007), shrimps (Lang et al 2004), fishes (Klapper et al 1998b;Anchelin et al 2011) and insects (Sasaki and Fujiwara 2000;Mohan et al 2011). Moreover, telomerase activity has been considered as cell proliferation and cell aging marker Belair et al 1997).…”

“…Like vertebrates (Forsyth et al 2002) and plants (Fitzgerald et al 1996), the distribution of telomerase activity has been studied in insects (Sasaki and Fujiwara 2000) and other invertebrates including sponges (Koziol et al 1998), lobster (Klapper et al 1998a), shrimps (Lang et al 2004), molluscs (Owen et al 2007), sea squirts (Sköld et al 2011) corals and algae (Zielke and Bodnar 2010). Subsequent to the detection of telomerase activity by Lang et al (2004) in Penaeus japonicus, there has been no further studies in this direction.…”