A helminth cestode parasite express an estrogen-binding protein resembling a classic nuclear estrogen receptor

作者：Guadalupe Ibarra Coronado Elizabeth; Escobedo Galileo; Nava Castro Karen; Jesus Ramses Chavez Rios; Hernandez Bello Romel; Garcia Varela Martin; Ambrosio Javier R; Reynoso Ducoing Olivia; Fonseca Linan Rocio; Ortega Pierres Guadalupe; Pavon Lenin; Eugenia Hernandez Maria; Morales Montor Jorge^*

来源：Steroids, 2011, 76(10-11): 1149-1159.

DOI：10.1016/j.steroids.2011.05.003

• Nuclear estrogen receptor
• Estradiol
• Taenia crassiceps
• Cysticercus
• Parasite
• Hormone receptors

The role of an estrogen-binding protein similar to a known mammalian estrogen receptor (ER) is described in the estradiol-dependent reproduction of the helminth parasite Taenia crassiceps. Previous results have shown that 17-beta-estradiol induces a concentration-dependent increase in bud number of in vitro cultured cysticerci. This effect is inhibited when parasites are also incubated in the presence of an ER binding-inhibitor (tamoxifen). RT-PCR assays using specific oligonucleotides of the most conserved ER sequences, showed expression by the parasite of a mRNA band of molecular weight and sequence corresponding to an ER. Western blot assays revealed reactivity with a 66 kDa protein corresponding to the parasite ER protein. Tamoxifen treatment strongly reduced the production of the T. crassiceps ER-like protein. Antibody specificity was demonstrated by immunoprecipitating the total parasite protein extract with anti-ER-antibodies. Cross-contamination by host cells was discarded by flow cytometry analysis. ER was specifically detected on cells expressing paramyosin, a specific helminth cell marker. Parasite cells expressing the ER-like protein were located by confocal microscopy in the subtegumental tissue exclusively. Analysis of the ER-like protein by bidimensional electrophoresis and immunoblot identified a specific protein of molecular weight and isoelectric point similar to a vertebrates ER. Sequencing of the spot produced a small fragment of protein similar to the mammalian nuclear ER. Together these results show that T. crassiceps expresses an ER-like protein which activates the budding of T. crassiceps cysticerci in vitro. To the best of our knowledge, this is the first report of an ER-like protein in parasites. This finding may have strong implications in the fields of host-parasite co-evolution as well as in sex-associated susceptibility to this infection, and could be an important target for the design of new drugs.

• 出版日期2011-10