a1 Institute of Biology, College of Biochemistry, Chemistry and Pharmacy, Universidad Nacional de Tucuman, Chacabuco 461, 3°, Tucumán 4000, Argentina.
a2 Instituto Superior de Investigaciones Biológicas (CONICET-UNT), Chacabuco 461, 4000, Tucumán, Argentina.
a3 Institute of Biology, College of Biochemistry, Chemistry and Pharmacy, Universidad Nacional de Tucuman, Chacabuco 461, 3°, Tucumán 4000, Argentina.
a4 Animal Production Department, College of Agriculture and Zootechnology, Universidad Nacional de Tucuman, Avenida Roca 1900, Tucumán 4000, Argentina.
In mammals, fertilization and preimplantation embryo development occurs in the oviduct. Cross-talk between the developing embryos and the maternal reproductive tract has been described in such a way as to show that the embryos modulate the physiology and gene expression of the oviduct. Different studies have indicated that transforming growth factor beta (TGF-β) can modulate the oviductal microenvironment and act as an autocrine/paracrine factor on embryo development. LEFTY2, a novel member of the TGF-β superfamily is involved in the negative regulation of other cytokines in this family such as nodal, activin, BMPs, TGF-β1 and Vg1. In previous studies, we have reported that LEFTY2 is differentially expressed in the rat oviduct during pregnancy. In this study, we describe the temporal pattern of LEFTY2 in pregnant and non-pregnant rat oviduct by western blotting, which showed higher levels of LEFTY2 on day 4 of pregnancy, a time at which the embryos are ending their journey along the oviduct. The cellular location of LEFTY2 was assessed by immunohistochemistry, which showed immunolabelling in the cytoplasm and at the apical surface of the oviductal epithelial cells. The oviductal fluid also presented a 26 kDa band, which corresponds to the biologically active form of this protein, at the preimplantation period of pregnancy, indicating LEFTY2 secretion to the lumen. As LEFTY2 is expressed at a high level just before the embryos pass to the uterus, its biological effect might be relevant and significant for the preimplantation stage of embryo development in the oviduct. The fact that embryos do not express LEFTY2 at this stage of development supports this hypothesis.
(Received April 22 2010)
(Accepted September 11 2010)
(Online publication December 21 2010)
c1 All correspondence to: D.C. Miceli. Institute of Biology, College of Biochemistry, Chemistry and Pharmacy, Universidad Nacional de Tucuman, Chacabuco 461, 3°, Tucumán 4000, Argentina. Tel: +54 381 4247752 ext 7099. Fax: +54 381 4107214. e-mail: email@example.com