A 3.7-kb cDNA encodes the carp JAK1 kinase of 1,156 amino acid residues. The overall amino acid sequence identity between carp JAK1 and murine JAK1, JAK2, JAK3, and human TYK2 is 57%, 35.5%, 31.3%, and 42.4%, respectively. In addition, carp JAK1 shows higher sequence homology to mammalian JAK1 in both the kinase-like (JH2) and kinase (JH1) domains (approximately 70% identity). Therefore, carp JAK1 is a homolog of mammalian JAK1. To investigate the possible function of JH2 domain, full-length, and various truncated forms of carp JAK1 were produced in the baculovirus system. Our results demonstrate that c-JH1 and c-JH2 associate with each other and c-JH2 can be tyrosine-phosphorylated by c-JAK1 and by c-JH(1 + 2). The JAK1 gene was also isolated from a carp genomic library and characterized. This gene is divided into 24 exons spanning at least 31 kb of genomic DNA. Exon 1 contains the 5'-untranslated region and exon 2 contains the putative translation initiation site. The 2.5-kb DNA region upstream of the transcription initiation site contains numerous potential binding sites for transcription factors including NF-IL6, HNF-5, AP1, GHF-5, and E2A. When this DNA fragment was placed upstream of the chloramphenicol acetyltransferase (CAT) reporter gene and transfected into a carp CF cell line, it could drive the synthesis of CAT enzyme 16 times more efficiently than the promoterless pCAT-Basic. Deletion analysis defined a positive regulatory region between -1,023 and -528. A smaller region (-181 to +59) without any typical TATA-box sequences, G + C-rich sequences, or other binding sequences for known transcription factors still had promoter activity. Constructs without this region did not have detectable promoter activity. This suggests that this region of DNA may play an important role in the expression of carp JAK1 gene.

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Cobra neurotoxin from Formosan cobra (Naja naja atra) venom is a compact globular protein having an intrinsic viscosity of 4.5 mL/g. The protein is stable in 7.5 M urea but can be denatured in 4.1 M guanidine hydrochloride or at elevated temperature (above 70 degrees C). Its conformation remains virtually the same in solvents of lower polarity than water such as 1,2-ethanediol or a mixed solvent of 1-propanol-1,2-ethanediol-water (5:1:1 by volume). The circular dichroism spectrum is "atypical" in water in that the peptide chromophores show a small negative circular dichroic (CD) band at 215 nm, a large positive one at 199 nm, and another large negative one below 190 nm. The CD pattern resembles to some extent that of a beta form but differs in both positions and magnitudes from the latter. It agrees qualitatively with the theoretical calculations of the reverse beta bends, suggesting that cobra toxin contains a considerable amount of beta turns and possibly a mixture of beta form and beta turns.

The crude venom of Formosan cobra (Naja naja atra) was separated into 12 fractions by CM‐Sephadex (C‐50) chromatography with ammonium acetate buffer by two‐stage gradient elution. Fr. I was proved to be a mixture of nucleotides and nucleosides. The toxicity was found in Fr. VIII (neurotoxic), X (cardiotoxic), XI (cardiotoxic), and XII (cardiotoxic). Glycerophosphatase, alkaline phosphomonoesterase, and 5′‐nucleotidase were found in Fr. III, V and IX, respectively. Phosphodiesterase was distributed in Frs. VI and VII, while lecithinase‐A (phospholipase‐A) was found in Frs. IV and V. Frs. VIII, IX and XII seem to be homogenous by the n‐terminal analysis and the paper electrophoresis.

There are two types of cDNA clones (designated al and a2) encoding the a subunit ofcarp gonadotropin. These two cDNAs are derived from different genes and encode proteins that differ by seven amino acid residues (three in the signal peptide and four in the mature polypeptide). Expression of these two cDNAs in insect cells by recombinant baculovirus revealed that the al subunit, after noncovalent association with the 3 subunit, has the same potency as the native a subunit purified from the pituitary. In contrast, the a2 subunit can associate with the fi subunit, but only to form an inactive gonadotropin. Competition of the a2 subunit with the al subunit for association with the (3 subunit decreases the gonadotropin activity of the a//] complex. In addition, both al and a2 subunits are secreted into the culture medium by insect cells and have an apparent molecular mass approximately 5 kDa higher than that of the native a subunit. These results indicate that the insect cell-derived al subunit is biologically active and that those four amino acid changes in the mature a2 protein affect the biological activity and thus provide valuable dues for the study of the structure-function relationship ofthe a subunit of glycoprotein hormones. The expression of glycoprotein hormone genes has been extensively studied. Human choriogonadotropin and its subunits can be produced in monkey cells by using eukaryotic expression vectors containing the metallothionein-1 promoter or the simian virus 40 regulatory elements (13-15). A vaccinia virus expression vector has been employed to produce useful amounts of the hormone and its subunits and to provide more information about the assembly of individual subunits and the nature of glycosylation (16). In this study, we used the baculovirus expression system (17) to express al and a2 cDNAs and to study the biological activity of these two a subunits.The family of glycoprotein hormones includes the pituitary hormones lutropin, follitropin, thyrotropin, and placental choriogonadotropin (1). Lutropin, follitropin, and choriogonadotropin act on the testes and ovaries to stimulate steroid synthesis and are collectively termed gonadotropins (GTHs). Each glycoprotein hormone is dimeric, containing a common a subunit and a hormone-specific /3 subunit that confers its biological specificity. The hormonal activity is expressed only after noncovalent association of these two subunits.The amino acid sequences of the a subunits of mammalian GTHs from several species (2) $To whom reprint requests should be addressed. 7486The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact.