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Abstract: Bombyx mori is a female-heterogametic organism (female, ZW; male, ZZ) that appears to have a putative feminizing gene (Fem) on the W chromosome. The paternally transmitted mutant W chromosome, Df(p Sa + p W + od )Fem, derived from the translocation-carrying W chromosome (p Sa + p W + od ), is inert as femaleness determinant. Moreover, this Df(p Sa + p W + od )Fem chromosome has been thought to have a female-killing factor because no female larvae having the Df(p Sa + p W + od )Fem chromosome are produced. Initially, to investigate whether the Df(p Sa + p W + od )Fem chromosome contains any region of the W chromosome or not, we analyzed the presence or absence of 12 W-specific RAPD markers. The Df(p Sa + p W + od )Fem chromosome contained 3 of 12 W-specific RAPD markers. These results strongly indicate that the Df(p Sa + p W + od )Fem chromosome contains the region of the W chromosome. Moreover, by using phenotypic and molecular markers, we confirmed that the Df(p Sa + p W + od )Fem chromosome is connected with a partially deleted Z chromosome and that this fused chromosome behaves as a Z chromosome during male meiosis. Furthermore, we demonstrated that the ZZW-type triploid female having the Df(p Sa + p W + od )Fem chromosome is viable. Therefore, we concluded that the Df(p Sa + p W + od )Fem chromosome does not have a female-killing factor but that partial deletion of the Z chromosome causes the death of the ZW-type diploid female having the Df(p Sa + p W + od )Fem chromosome. Additionally, our results of detailed genetic analyses strongly indicate that the female-killing chromosome composed of the Df(p Sa + p W + od )Fem chromosome and deleted Z chromosome was generated by translocation between the Z chromosome and the translocation-carrying W chromosome, p Sa + p W + od .

Abstract The sex chromosome constitution of the silkworm, Bombyx mori, is ZW in the female and ZZ in the male. Very little molecular information is available about the Z chromosome in Lepidoptera, although the topic is interesting because of the absence of gene dosage compensation in this chromosome. We constructed a 320-kb BAC contig around the Bmkettin gene on the Z chromosome in Bombyx and determined its nucleotide sequence by the shotgun method. We found 13 novel protein-coding sequences in addition to Bmkettin. All the transposable elements detected in the region were truncated, and no LTR retrotransposons were found, in stark contrast to the situation on the W chromosome. In this 320-kb region, four genes for muscle proteins (Bmkettin, Bmtitin1, Bmtitin2, and Bmprojectin) are clustered, together with another gene (Bmmiple) on the Z chromosome in B. mori; their orthologs are also closely linked on chromosome 3 in Drosophila, suggesting a partial synteny. Real-time RT-PCR experiments demonstrated that transcripts of 13 genes of the 14 Z-linked genes found accumulated in larger amounts in males than in female moths, indicating the absence of gene dosage compensation. The implications of these findings for the evolution and function of the Z chromosome in Lepidoptera are discussed.

Abstract. Kynurenine 3-monooxygenase (KMO, EC 1.14.13.9), which catalyzes the oxidation of kynurenine to 3-hydroxykynurenine, is involved in the synthesis of ommochrome pigments in insects. A silkworm mutant, white egg 1 (w-1), has been shown to be deficient in this enzyme activity. The mutant is characterized morphologically by its white eyes and the fact that the females lay white eggs. To analyze the relationship between the KMO gene and the mutation, we first determined the entire sequence of a full-length 2.0-kb cDNA and examined its expression pattern in the wild type. The cDNA sequence contains one ORF encoding a polypeptide of 456 amino acids, and transcripts were detected in the larval Malpighian tubules and the pupal ovaries, but not in other tissues. Southern analysis and nucleotide sequencing showed that the KMO gene is present in a single copy and consists of ten exons distributed over a 16-kb region. Comparison of the transcripts between the wild type and mutant silkworms showed that the wild type expressed a single transcript, whereas the mutant exhibited markedly reduced amounts of two transcripts with sizes of 2.0 kb and 1.8 kb. Nucleotide sequence analysis of these mutant transcripts indicated that sequences corresponding to the ninth and tenth exons were missing. Inverse PCR and Southern analysis of the mutant gene demonstrated that the corresponding genomic region was deleted in the w-1 mutant.

To characterize the structural features common toPao-like retrotransposons, we analyzed two lambda phage clones which contain thePao-like elements from the silkworm speciesBombyx moriandB.mandarina, and copies ofPaoitself andninjaofDrosophila simulans, amplified by PCR. We previously identified two randomly amplified polymorphic DNAs (RAPDs), W-Kamikaze and W-Yamato, fromB.moriandB.mandarina, which are part of two novelPao-like retrotransposons,KamikazeandYamato, respectively. Complete characterization of these and other elements of this group reported here shows thatPao-like elements have common features that distinguish them from the other groups of LTR-retrotransposons. While the elements of the Ty1-copiagroup encode only one cysteine and histidine (Cys) motif in theirgag-like region, thePao-like elements specify three Cys motifs. The highly conserved D(35)E motif in the integrase domain of the retrotransposon polyprotein seems to be conserved inPao-like elements, but the number of amino acid residues between D and E varies and is greater than 35. A comparison of the deduced amino acid sequences of the reverse transcriptase domain revealed that thePao-like elements are members of neither the Ty1-copianor thegypsy-Ty3 groups. Therefore, we confirmed that the long-terminal-repeat (LTR) retrotransposons should be divided into three major groups (or families), namely the Ty1-copia,gypsy-Ty3, andPao-like groups.

Clinical practice guidelines are expanding their scope of authority from clinical decision making to collective policy making, and promise to gain ground as resource allocation tools in coming years. A close examination of how guidelines approach patient selection criteria offers insight into their ethical implications when used as resource allocation or rationing instruments. The purposes of this paper are: a) to examine the structure of allocative reasoning found in clinical guidelines; b) to identify the ethical principles implied and compare how guidelines enact these principles with how explicit systems-level rationing exercises and health policy analyses have approached them; and c) to offer some preliminary suggestions for how these ethical issues might be addressed in the process of guideline development. The resulting framework can be used by guideline developers and users to understand and address some of the ethical issues raised by guidelines for the use of scarce technologies.

By using porcine elastase I cDNA as a probe, we have isolated two different but closely related cDNAs encoding elastase-like proteases from a human pancreatic cDNA library. The amino acid sequences deduced from the cloned cDNA sequences showed 56-61% identity with those of both pancreatic elastases I and II, similar to the homology between elastases I and II. The active form of the elastase-like proteases appeared to be composed of 242 amino acids and preceded by a signal peptide and propeptide of 28 amino acids. Dot blot analysis of various tissue mRNAs demonstrated that the genes for the cloned cDNAs are expressed at a high level only in the pancreas. In addition, sequence analysis of the cloned genomic genes corresponding to one of the cDNAs showed that they are members of the elastase gene family. These results indicate that the two enzymes encoded by the cDNAs should be classified into a third class of elastase isozyme. Therefore, we designated them as human pancreatic elastases IIIA and IIIB. They strongly resembled cholesterol-binding pancreatic protease, suggesting that they may possess not only a digestive function but also function(s) related to cholesterol metabolism or transport in the intestine.

Genetic and biochemical analyses were performed on the cytoplasmic cap-binding complex (eukaryotic initiation factor (eIF) 4F) of Schizosaccharomyces pombe. Genomic and cDNA sequencing of the S. pombe gene (tif1) encoding the cap-binding component eIF4E revealed the presence of two introns in a reading frame of 219 codons. The encoded sequence of 218 amino acids shows a greater degree of identity to the mammalian eIF4E sequence than does its counterpart from Saccharomyces cerevisiae. In particular, unlike its S. cerevisiae counterpart, S.pombe eIF4E has a C-terminal Ser209 within the motif KSGST that is a site of phosphorylation in hamster and rabbit eIF4E. Of relevance to its potential regulatory role, eIF4E was found to be encoded by an mRNA with a six-nucleotide leader and to be of low abundance in vivo. Cross-linking experiments identified S. pombe eIF4E as the major cap-binding protein while a further protein, p36, also showed cap-dependent binding. eIF4A was not associated with the cap-binding complex. While S. pombe eIF4E was shown capable of binding S. cerevisiae p20, an equivalent protein was absent from the eIF4F complex isolated from S. pombe cells. S. pombe 4F therefore shows a remarkable combination of structural and functional properties, some of which it shares with its higher and its lower eukaryotic counterparts.