Members of a Large Retroposon Family Are Determinants of Post-Transcriptional Gene Expression in Leishmania

PLoS Pathogens

Najib M. A El-Sayed¹  Elodie Ghedin²  Martin Smith²  Barbara Papadopoulou³  Gustavo Coutinho Cerqueira³  Frédéric Bringaud⁴  Annie Rochette⁵  Michaela Müller⁶ 

[1] Departamento de Bioquimica e Imunologica, Universidade Federal de Minas Gerais, Minas Gerais, Brazil;Department of Medical Biology, Faculty of Medicine, Laval University, Quebec, Canada;Infectious Diseases Research Center, Centre Hospitalier de l'Université Laval Research Center, Quebec, Canada;Laboratoire de Génomique Fonctionnelle des Trypanosomatides, Université Victor Segalen Bordeaux 2, Bordeaux, France;The Institute for Genomic Research, Rockville, Maryland, United States of America;UMR-5234 CNRS, Bordeaux, France

关键词: Sequence alignment;    Trypanosoma brucei gambiense;    Multiple alignment calculation;    Messenger RNA;    Sequence motif analysis;    Trypanosoma;    Sequence analysis;    Gene expression;   

DOI  :  10.1371/journal.ppat.0030136

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Trypanosomatids are unicellular protists that include the human pathogens Leishmania spp. (leishmaniasis), Trypanosoma brucei (sleeping sickness), and Trypanosoma cruzi (Chagas disease). Analysis of their recently completed genomes confirmed the presence of non–long-terminal repeat retrotransposons, also called retroposons. Using the 79-bp signature sequence common to all trypanosomatid retroposons as bait, we identified in the Leishmania major genome two new large families of small elements—LmSIDER1 (785 copies) and LmSIDER2 (1,073 copies)—that fulfill all the characteristics of extinct trypanosomatid retroposons. LmSIDERs are ∼70 times more abundant in L. major compared to T. brucei and are found almost exclusively within the 3′-untranslated regions (3′UTRs) of L. major mRNAs. We provide experimental evidence that LmSIDER2 act as mRNA instability elements and that LmSIDER2-containing mRNAs are generally expressed at lower levels compared to the non-LmSIDER2 mRNAs. The considerable expansion of LmSIDERs within 3′UTRs in an organism lacking transcriptional control and their role in regulating mRNA stability indicate that Leishmania have probably recycled these short retroposons to globally modulate the expression of a number of genes. To our knowledge, this is the first example in eukaryotes of the domestication and expansion of a family of mobile elements that have evolved to fulfill a critical cellular function.

【 授权许可】

CC BY