title: Expression of CD44 in sheep  oocytes and preimplantation embryos.
abstract: The  CD44 family belongs to a larger group of hyaluronic acid-binding proteins and  plays important roles in oocyte maturation, fertilization and preimplantational  embryo development. We analyzed the CD44 receptor in sheep oocytes and embryos.  Immature oocytes (N = 66) were obtained from a local abattoir; mature oocytes  (N = 35) and embryos (N = 41) were obtained by laparotomy from adult hair ewes  submitted to ovarian stimulation treatment. The CD44 mRNA was detected by  hemi-nested PCR, after reverse transcription, while proteins were located by  indirect immunofluorescence, using anti-human CD44 monoclonal antibody. Human  lymphocytes and immature bovine oocytes were used as positive and negative  controls, respectively. Assessment of the oocyte nuclear stages as well as classification  of the embryonic development stage were made with Hoechst 33342 staining.  Indirect immunofluorescence detected CD44 expression on the surface of mature  oocytes and embryos; immature oocytes did not take up the stain. These findings  were supported by the RT-PCR data, which showed no mRNA templates for CD44,  even after two consecutive amplifications, in material from immature oocytes  and cumulus cells. The CD44 amplicons were detected after a second hemi-nested  PCR in mature oocytes and embryos. The finding of CD44 in mature oocytes and  preimplantational embryos could reflect the expression profile of hyaluronic  acid during terminal folliculogenesis and preimplantational embryo development  in sheep.
authors.affiliation: Laboratório de Fisiologia e Controle da Reprodução, Faculdade de Veterinária, Universidade Estadual do Ceará, Fortaleza, CE, Brasil.
authors.forename: J V
authors.initials: JV
authors.lastname: Luz
authors.forename: A S
authors.initials: AS
authors.lastname: Alcântara-Neto
authors.forename: R I T P
authors.initials: RI
authors.lastname: Batista
authors.forename: J M G
authors.initials: JM
authors.lastname: Souza
authors.forename: D I A
authors.initials: DI
authors.lastname: Teixeira
authors.forename: L M
authors.initials: LM
authors.lastname: Melo
authors.forename: V J F
authors.initials: VJ
authors.lastname: Freitas
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D001483:Base Sequence; D001755:Blastocyst; D017931:DNA Primers; D005260:Female; D018960:Hyaluronan Receptors / Q000235:genetics / Q000276:immunology*; D009865:Oocytes / Q000276:immunology*; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012756:Sheep
chemical_list: D000911:Antibodies, Monoclonal; D017931:DNA Primers; D018960:Hyaluronan Receptors; D012333:RNA, Messenger