A mouse oocyte-specific protein that binds to a region of mZP3 promoter responsible for oocyte-specific mZP3 gene expression.
The gene encoding mZP3, the mouse sperm receptor, is expressed exclusively in growing oocytes during oogenesis. To investigate the molecular basis of oocyte-specific mZP3 gene expression, we generated several lines of mice harboring a transgene that contains 470 bp of mZP3 gene 5'-flanking sequence (nucleotides -470 to +10) fused to the firefly luciferase gene coding region. Three of four expressing transgenic lines exhibited luciferase activity only in growing oocytes, suggesting that the 470-bp fragment is sufficient to direct Iocyte-specific expression of the luciferase gene. Results of DNase I footprinting and gel mobility shift assays suggested the presence of an ovary-specific protein that binds to a small region (nucleotides-99 to -86) within the 470-bp fragment of the mZP3 promoter, with 5'-G(G/A)T(G/A)A-3' representing the minimal sequence required for binding. Southwestern (DNA-protein) gel blots revealed the presence of an oocyte-specific, approximately 60,000-Mr protein, called OSP-1, that binds to the minimal sequence. Changes in levels of OSP-1 during oogenesis and early cleavage are consistent with the pattern of mZP3 gene expression during these developmental stages in mice. Therefore, OSP-1 may be a mammalian oocyte-specific transcription factor involved in regulating oocyte-specific mZP3 gene expression.
Schickler
M
M
Department of Cell and Developmental Biology, Roche Institute of Molecular Biology, Nutley, New Jersey 07110.
Lira
S A
SA
Kinloch
R A
RA
Wassarman
P M
PM
D000818:Animals; D001483:Base Sequence; D001667:Binding, Competitive; D004247:DNA; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004527:Egg Proteins; D005786:Gene Expression Regulation; D006023:Glycoproteins / Q000235:genetics*; D008156:Luciferases / Q000378:metabolism; D008562:Membrane Glycoproteins; D051379:Mice; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D009865:Oocytes / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D011956:Receptors, Cell Surface; D000072216:Zona Pellucida Glycoproteins
D004268:DNA-Binding Proteins; D004527:Egg Proteins; D006023:Glycoproteins; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; D000072216:Zona Pellucida Glycoproteins; D004247:DNA; D008156:Luciferases