Activation of transcription and retrotransposition of a novel retroelement, Steamer, in neoplastic hemocytes of the mollusk Mya arenaria

Gloria Arriagada, Michael J. Metzger, Annette F. Muttray, James Sherry, Carol Reinisch, Craig Street, W. Ian Lipkin, Stephen P. Goff

Research output: Contribution to journalArticlepeer-review

32 Citations (Scopus)

Abstract

Bivalve mollusks of the North Atlantic, most prominently the soft shell clam Mya arenaria, are afflicted with an epidemic transmissible disease of the circulatory system closely resembling leukemia. The disease is characterized by a dramatic expansion of blast-like cells in the hemolymph with high mitotic index. Examination of hemolymph of diseased clams revealed high levels of reverse transcriptase activity, the hallmark of retroviruses and retroelements. By deep sequencing of RNAs from hemolymph, we identified transcripts of a novel retroelement, here named Steamer. The DNA of the element is marked by long terminal repeats and encodes a single large protein with similarity to mammalian retroviral Gag-Pol proteins. Steamer mRNA levels were specifically elevated in diseased hemocytes, and high expression was correlated with disease status. DNA copy number per genome was present at enormously high levels in diseased hemocytes, indicative of extensive reverse transcription and retrotransposition. Steamer activation in M. arenaria is an example of a catastrophic induction of genetic instability that may initiate or advance the course of leukemia.

Original languageEnglish
Pages (from-to)14175-14180
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume111
Issue number39
DOIs
Publication statusPublished - 30 Sep 2014

Keywords

  • Disseminated neoplasia
  • Hemic neoplasia
  • Integration
  • Mobile genetic element
  • Retrotransposon

ASJC Scopus subject areas

  • General

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