Author Posting. © The Author(s), 2010. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Molecular and Biochemical Parasitology 174 (2010): 62-65, doi:10.1016/j.molbiopara.2010.05.010.
We quantified mRNA abundance from 10 stages in the Giardia lamblia life cycle in vitro using
Serial Analysis of Gene Expression (SAGE). 163 abundant transcripts were expressed
constitutively. 71 transcripts were upregulated specifically during excystation and 42 during
encystation. Nonetheless, the transcriptomes of cysts and trophozoites showed major
differences. SAGE detected co-expressed clusters of 284 transcripts differentially expressed in
cysts and excyzoites and 287 transcripts in vegetative trophozoites and encysting cells. All
clusters included known genes and pathways as well as proteins unique to Giardia or
diplomonads. SAGE analysis of the Giardia life cycle identified a number of kinases,
phosphatases, and DNA replication proteins involved in excystation and encystation, which
could be important for examining the roles of cell signaling in giardial differentiation. Overall,
these data pave the way for directed gene discovery and a better understanding of the biology
of Giardia lamblia.
BJD, DSR, and FDG were supported by NIH grants AI42488, GM61896, DK35108, and
AI051687. DP and SGS were supported by grants from the Swedish Natural Science Research
Council, the Swedish Medical Research Council, and the Karolinska Institutet. AGM, SRB,
SPP, and MJC were supported by NIH grant AI51089 and by the Marine Biological Laboratory’s
Program in Global Infectious Diseases, funded by the Ellison Medical Foundation.
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