Involvement Of Neb-Colloostatin, A Collagen-Related Peptide, In Early Vitellogenesis Of The Grey Fleshfly

During the purification procedure of the first folliculostatin of the grey fleshfly Neobellieria bullata, the Trypsin-Modulating Oostatic Factor (Neb-TMOF), a second factor with oostatic activity, was discovered. Here we report the primary structure and effects on oocyte development of the latter factor. The amino acid sequence was determined as H-SIVPLGLPVPIGPIVVGPR-OH. Because of structural sequence similarities with parts of several known collagens and because of its oostatic activity, we named the factor Neb-colloostatin. The synthetic peptide inhibits yolk uptake by previtellogenic oocytes and might be the factor thai determines that per ovariole only one follicle develops at a time.