Genetic analysis in Drosophila has shown that engrailed (en) plays an important role in segmentation and neurogenesis. A closely related gene, invected (in), is coexpressed with en in the posterior developmental compartments where en is known to specify cell state. We report here the isolation of two en-like cDNAs from the middle silk glands of Bombyx mori larvae. Sequence analysis revealed that they are the counterparts of Drosophila en and in. Four highly conserved domains, including the homeodomain, were identified in these En and In proteins from Bombyx and Drosophila. In addition, two en-specific and one in-specific domains could also be found. These structurafly homologous genes might share a similar role in Bombyx development. They were found to be coexpressed in the middle silk gland but not in the posterior silk gland during the fourth molt/fifth intermolt period. We speculate that these Bombyx en-like genes might be involved in the compartmentalization of the silk gland.cently, we reported that the promoters of the silk protein genes contain clustered homeodomain binding sites (34,35) and that several putative homeodomain-containing proteins that interact with these sites can be found in the silk gland extracts (36). As part of our efforts to characterize the homeobox genes that are possibly involved in the regulation of the silk protein genes, several homeobox-containing cDNAs have been isolated from silk gland cDNA libraries. In this report, we describe the molecular characterization oftwo Bombyx en-like cDNAs. Sequence analysis reveals that they are the counterparts ofDrosophila en and in. We have named the corresponding genes Bombyx engrailed (Bm en) and Bombyx invected (Bm in), respectively. Throughout the fourth molt/fifth intermolt period, they are coexpressed in the middle silk gland but not in the posterior silk gland. A hypothesis that these en-like genes are involved in specifying compartments in the silk gland is discussed.
Pulmonary metastasectomy for HCC in selected patients resulted in relatively good outcomes with regard to OS. History of recurrence and serum DCP levels were shown to be candidates of prognostic factors for OS.
Background: Abundant availability of homeotic mutants in Bombyx mori provides us with clues to study the body plan of the silkworm. Previous studies indicated that the E Ca /E Ca and E N /E N embryos, which reveal drastic morphological changes (Itikawa 1943, 1952) lack the homologue of abd-A and the homologues of abd-A and Ubx, respectively (Ueno et al. 1992). It will be interesting to characterize a mutant named Nc, the locus of which was mapped about 1.4 cm apart from the E loci (Itikawa 1944, 1952).
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