Differential dissolved protein expression throughout the life cycle of Giardia lamblia.
Giardia lamblia (G. lamblia) has a simple life cycle that alternates between a cyst and a trophozoite, and this parasite is an important human and animal pathogen. To increase our understanding of the molecular basis of the G. lamblia encystment, we have analyzed the soluble proteins expressed by trophozoites and cysts extracted from feces by quantitative proteomic analysis. A total of 63 proteins were identified by isobaric tags for relative and absolute quantitation (iTRAQ) labeling, and were categorized as cytoskeletal proteins, a cell-cycle-specific kinase, metabolic enzymes and stress resistance proteins. Importantly, we demonstrated that the expression of seven proteins differed significantly between trophozoites and cysts. In cysts, the expression of three proteins (one variable surface protein (VSP), ornithine carbamoyltransferase (OTC), β-tubulin) increased, whereas the expression of four proteins (14-3-3 protein, α-tubulin, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), protein disulfide isomerase 2 (PDI-2)) decreased significantly when compared with the levels of these proteins in trophozoites. The mRNA expression patterns of four of these proteins (OTC, α-tubulin, GAPDH, VSP) were similar to the expression levels of the proteins. These seven proteins appear to play an important role in the completion of the life cycle of G. lamblia.
College of Animal Science and Veterinary Medicine, Jilin University, 5333 Xi'an Road, Changchun 130062, China.
Li
L
Lingdan
Gong
G
Pengtao
Li
L
Wenchao
Li
L
Jianhua
Yang
Y
Ju
Liu
L
Chengwu
Li
L
He
Zhang
Z
Guocai
Ren
R
Wenzhi
Chen
C
Yujiang
Zhang
Z
Xichen
D000818:Animals; D000953:Antigens, Protozoan / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D004285:Dogs; D005243:Feces / Q000469:parasitology; D015870:Gene Expression; D016829:Giardia lamblia / Q000201:enzymology / Q000254:growth & development* / Q000378:metabolism*; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D008018:Life Cycle Stages / Q000502:physiology*; D008565:Membrane Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D009954:Ornithine Carbamoyltransferase / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D020543:Proteome; D015800:Protozoan Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D014158:Transcription, Genetic; D053058:Trophozoites / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism; D014404:Tubulin / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism
D000953:Antigens, Protozoan; D008565:Membrane Proteins; D020543:Proteome; D015800:Protozoan Proteins; D014404:Tubulin; C103927:Vsp protein, Giardia intestinalis; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D009954:Ornithine Carbamoyltransferase