Cryptic Protein Research Articles

The ability of hamster oolemma to fuse with spermatozoa: Its acquisition during oogenesis and loss after fertilization

To determine when the growing hamster oocyte gains the ability to fuse with the spermatozoon, oocytes at various stages of development were collected from ovaries, and zona-pellucida-free oocytes were inseminated in vitro with acrosome-reacted spermatozoa. Very small primary oocytes were unable to fuse with spermatozoa. Oocytes first became competent to fuse with spermatozoa when they had grown to about 20 microns in diameter. The acquisition of fusibility coincided with the first appearance of zona pellucida material and oolemma microvilli. The fusibility of the oolemma increased as the oocyte grew, reaching a maximum when the oocyte reached the metaphase of the second meiosis. The fusibility of the oolemma was reduced drastically after fertilization, and was lost completely by the 8-cell stage. The appearance and subsequent disappearance of a putative fusion-mediating molecule in the oolemma is proposed. Since this molecule is fairly resistant to proteinase digestion, at least in the hamster, it could be a cryptic protein or a glycolipid.

Activation of a cryptic crystal protein gene of Bacillus thuringiensis subspecies kurstaki by gene fusion and determination of the crystal protein insecticidal specificity

DNA hybridization with the insecticidal crystal protein gene cryllA (formerly cryBl) of Bacillus thuringiensis supspecies kurstaki has shown that subspecies kurstaki contains a cryllA-related sequence in addition to the cryllA gene (Donovan et al., 1988a). We have cloned the cryllA-related sequence and have determined that the sequence, which has been designated cryllB, is 89% identical to the cryllA gene. Recombinant B. thuringiensis cells harbouring the cloned cryllB gene produced very little CryllB protein. A high level of production of the CryllB protein was achieved by fusing the regulatory region of the crylllA crystal protein gene to the cryllB gene. The CryllB protein was found to be highly toxic to Lymantria dispar, Heliothis virescens and Trichoplusia ni, and was not toxic to Aedes aegypti.

Subcellular localization of proteins encoded by the phenotypically cryptic plasmid of Neisseria gonorrhoeae: biological evidence for outer membrane association of the cppB gene product

Almost all clinical isolates of Neisseria gonorrhoeae harbour a plasmid of 4.2 kb with no known function. A genetic model based on the DNA sequence of the plasmid, with ten open reading frames, has been proposed by Korch et al., (1985). To address the question of the function of the encoded proteins, some of which are expressed when the plasmid is harboured by Escherichia coli, the subcellular locations of such proteins were investigated in minicells of Escherichia coli DS410. The protein CppB, earlier proposed to be a membrane-spanning polypeptide, was found associated with the outer membrane. Up to five other cryptic plasmid proteins were found to be localized in the periplasm.