Oocyte-specific expression of mouse Zp-2: developmental regulation of the zona pellucida genes.
The zona pellucida surrounds all mammalian oocytes and plays a vital role at fertilization and in early development. The genes that code for two of the mouse zona proteins (ZP2 and ZP3) represent a developmentally regulated set of genes whose expression serves as markers of mouse oocyte growth and differentiation. We previously characterized the single-copy Zp-3 gene and showed that its expression is oocyte specific and restricted to a narrow window of oocyte development. We now define the Zp-2 gene transcript and show that it is coordinately expressed with Zp-3 only during the 2-week growth phase of oogenesis that occurs prior to ovulation. Like Zp-3, the expression of Zp-2 is restricted to oocytes, and, although not detectable in resting oocytes, both ZP2 and ZP3 transcripts accumulate to become very abundant messengers in 50-microns-diameter oocytes. Ovulated eggs contain ZP2 and ZP3 transcripts which are 200 nucleotides shorter than those found in growing oocytes and have an abundance of less than 5% of the peak levels. In an attempt to understand the molecular details associated with the developmentally regulated, tissue-specific gene expression of the zona genes, the Zp-2 genetic locus has been characterized and its 5' flanking sequences have been compared with those of Zp-3. Both genes contain three short (8- to 12-base-pair) DNA sequences of 80 to 88% identity located within 250 base pairs of their transcription start sites.
Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892.
L F
LF
Liang
S M
SM
Chamow
J
J
Dean
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D002478:Cells, Cultured; D004527:Egg Proteins; D005091:Exons; D005260:Female; D005786:Gene Expression Regulation; D005796:Genes; D006023:Glycoproteins / Q000235:genetics*; D007438:Introns; D008562:Membrane Glycoproteins; D051379:Mice; D008969:Molecular Sequence Data; D009865:Oocytes / Q000502:physiology*; D010063:Ovum / Q000502:physiology*; D011487:Protein Conformation; D012313:RNA / Q000235:genetics / Q000302:isolation & purification; D012333:RNA, Messenger / Q000235:genetics; D011956:Receptors, Cell Surface; D012689:Sequence Homology, Nucleic Acid; D014158:Transcription, Genetic; D015044:Zona Pellucida / Q000502:physiology*; D000072216:Zona Pellucida Glycoproteins
D004527:Egg Proteins; D006023:Glycoproteins; D008562:Membrane Glycoproteins; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D000072216:Zona Pellucida Glycoproteins; C000606520:Zp2 protein, mouse; C000606521:Zp3 protein, mouse; D012313:RNA