Regulated expression of Wnts and Frizzleds at specific stages of follicular development in the rodent ovary.
Wnt ligands and Frizzled (Fz) G protein-coupled receptors impact cell fate, including embryonic development of the ovary. Because the role of these regulatory molecules during follicular development in the adult is not known, an RT-PCR survey was done. Wnt-4, Fz-4, and Fz-1 were among the transcripts detected, and each exhibited a specific pattern of expression. Fz-1 mRNA was low in preovulatory follicles of PMSG-treated mice but was increased within 4-12 h after an ovulatory surge of human CG. By in situ analysis, Fz-1 transcripts increased first in the theca cells and then in the granulosa cells of ovulating follicles but were low in corpora lutea. In contrast, Wnt-4, a critical factor in early ovarian development, was expressed in small preantral follicles. In addition, Wnt-4 was detected in preovulatory follicles and exhibited high levels in corpora lutea. A potential receptor for Wnt-4 in corpora lutea is Fz-4 that was also elevated in this tissue. Although Wnt-4 has been shown to function downstream of the PR in other tissues, Wnt-4 was not altered in follicles of PR-null mice that fail to ovulate. Rather expression of Fz-1 was lower in ovaries of PR knockout mice, compared with normal littermates. Thus, specific Wnt/Fz are expressed at distinct stages of follicular development, suggesting multiple functions for this signaling pathway in the ovary.
Hsieh
Minnie
M
Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030, USA.
Johnson
Mac A
MA
Greenberg
Norman M
NM
Richards
JoAnne S
JS
D000818:Animals; D015153:Blotting, Western; D003338:Corpus Luteum / Q000378:metabolism; D017931:DNA Primers; D005260:Female; D051157:Frizzled Receptors; D006107:Granulosa Cells / Q000378:metabolism; D017403:In Situ Hybridization; D008024:Ligands; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D006080:Ovarian Follicle / Q000502:physiology*; D010053:Ovary / Q000378:metabolism*; D014176:Protein Biosynthesis; D011506:Proteins / Q000235:genetics*; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis* / Q000235:genetics*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000302:isolation & purification; D051381:Rats; D017207:Rats, Sprague-Dawley; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; D017981:Receptors, Neurotransmitter / Q000096:biosynthesis* / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic; D051153:Wnt Proteins; D029961:Zebrafish Proteins
D017931:DNA Primers; C489740:FZD1 protein, human; D051157:Frizzled Receptors; C489739:Fzd1 protein, mouse; C498581:Fzd4 protein, mouse; C498582:Fzd4 protein, rat; D008024:Ligands; D011506:Proteins; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; D017981:Receptors, Neurotransmitter; D051153:Wnt Proteins; D029961:Zebrafish Proteins; C078603:Fzd1 protein, rat