| First Author | De Stasio R | Year | 1999 |
| Journal | Mol Reprod Dev | Volume | 52 |
| Issue | 2 | Pages | 126-34 |
| PubMed ID | 9890742 | Mgi Jnum | J:51680 |
| Mgi Id | MGI:1321447 | Doi | 10.1002/(SICI)1098-2795(199902)52:2<126::AID-MRD2>3.0.CO;2-O |
| Citation | De Stasio R, et al. (1999) Isolation, characterization and molecular cloning of cathepsin D from lizard ovary: changes in enzyme activity and mRNA expression throughout ovarian cycle. Mol Reprod Dev 52(2):126-34 |
| abstractText | During vitellogenesis, the oocytes of oviparous species accumulate in the cytoplasm a large amount of proteic nutrients synthetized in the liver. Once incorporated into the oocytes, these nutrients, especially represented by vitellogenin (VTG) and very low-density lipoprotein (VLDL), are cleaved into a characteristic set of polypeptides forming yolk platelets. We have studied the molecular mechanisms involved in yolk formation in a reptilian species Podarcis sicula, a lizard characterized by a seasonal reproductive cycle. Our results demonstrate the existence in the lizard ovary of an aspartic proteinase having a maximal activity at acidic pH and a molecular mass of 40 kDa. The full-length aspartic proteinase cDNA produced from total RNA by RT-PCR is 1,442 base pairs long and encodes a protein of 403 amino acids. A comparison of the proteic sequence with aspartic proteinases from various sources demonstrates that the lizard enzyme is a cathepsin D. Lizard ovarian cathepsin D activity is maximal in June, in coincidence with vitellogenesis and ovulation, and is especially abundant in vitellogenic follicles and in eggs. Ovarian cathepsin D activity can be enhanced during the resting period by treatment with FSH in vivo. Northern blot analysis shows that cathepsin D mRNA is exceedingly abundant during the reproductive period, and accumulates preferentially in previtellogenic oocytes. |
