title: Developmental regulation of hyaluronan-binding protein (RHAMM/IHABP) expression in early bovine embryos.
abstract: Hyaluronan or hyaluronic acid (HA) is a normal component of mammalian follicular, oviduct, and uterine fluids. Granulosa and expanding cumulus cells secrete large amounts of HA, and when HA is added in maturation and culture media, it improves the developmental potential of oocytes and embryos. HA regulates gene expression, signaling, proliferation, motility, adhesion, and morphogenesis. Many of these biological activities of HA are mediated through binding to the receptor for HA-mediated motility/intracellular HA-binding protein (RHAMM/IHABP). We evaluated the presence and dynamics of RHAMM/IHABP mRNA and protein expression in different stages of in vitro-produced bovine embryos using quantitative reverse transcriptase-real time-polymerase chain reaction and immunohistochemistry. We also analyzed the effects of different culture systems on the relative abundance of RHAMM/IHABP transcripts. RHAMM/IHABP mRNA levels decreased from the 2-cell to the 16-cell stage, increased again at the morula stage, and reached their highest level at the expanded blastocyst stage. RHAMM/IHABP mRNA abundance was significantly (P < 0.05) lower in embryos recovered in serum-containing medium than in embryos from serum-free media. Immunohistochemistry revealed the presence of RHAMM/IHABP first in 8-cell stages. Whereas RHAMM staining in 8-cell and morula stages was intense, it was weaker in blastocysts. Embryonic secretion of HA increased from the 2-cell stage until the 8-cell stage and then decreased in 16-cell embryos. After this, HA secretion increased in expanded and hatched blastocyst stages. These data suggest that the positive effects of HA on in vitro-produced bovine embryos may be mediated at least in part by RHAMM/IHABP.
authors.affiliation: Department of Molecular Animal Breeding and Biotechnology, LMU, D-85764 Oberschleissheim, Germany. m.stojkovic@gen.vetmed.uni-muenchen.de
authors.forename: Miodrag
authors.initials: M
authors.lastname: Stojkovic
authors.forename: Ottheinz
authors.initials: O
authors.lastname: Krebs
authors.forename: Sabine
authors.initials: S
authors.lastname: Kölle
authors.forename: Katja
authors.initials: K
authors.lastname: Prelle
authors.forename: Volker
authors.initials: V
authors.lastname: Assmann
authors.forename: Valeri
authors.initials: V
authors.lastname: Zakhartchenko
authors.forename: Fred
authors.initials: F
authors.lastname: Sinowatz
authors.forename: Eckhard
authors.initials: E
authors.lastname: Wolf
mesh_terms: D000818:Animals; D001483:Base Sequence; D002417:Cattle; D018076:DNA, Complementary / Q000235:genetics; D004622:Embryo, Mammalian / Q000378:metabolism*; D005314:Embryonic and Fetal Development / Q000235:genetics; D016326:Extracellular Matrix Proteins / Q000235:genetics* / Q000378:metabolism*; D005260:Female; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D018960:Hyaluronan Receptors / Q000235:genetics* / Q000378:metabolism*; D007150:Immunohistochemistry; D008969:Molecular Sequence Data; D011247:Pregnancy; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012689:Sequence Homology, Nucleic Acid
chemical_list: D018076:DNA, Complementary; D016326:Extracellular Matrix Proteins; D018960:Hyaluronan Receptors; D012333:RNA, Messenger; C098946:hyaluronan-mediated motility receptor