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The development of characteristic visceral asymmetries along the left-right (LR) axis in an initially bilaterally symmetrical embryo is an essential feature of vertebrate patterning. The allelic mouse mutations inversus viscerum (iv) and legless (lgl) produce LR inversion, or situs inversus, in half of live-born homozygotes. This suggests that the iv gene(More)
Ceramide produced by sphingomyelinases (SMases) has been recognized as an important second messenger in growth factor receptor signaling. Tumor necrosis factor (TNF), through binding to the 55 kDa TNF receptor (TNF-R55), rapidly activates two distinct types of SMase, a membrane-associated neutral (N-)SMase, and an endosomal acidic (A)-SMase. N-SMase and(More)
The patterning of the mammalian brain is orchestrated by a large battery of regulatory genes. Here we examine the developmental function of the Gsh-2 nonclustered homeobox gene. Whole-mount and serial section in situ hybridizations have been used to better define Gsh-2 expression domains within the developing forebrain, midbrain, and hindbrain. Gsh-2(More)
A novel murine dispersed homeobox gene, designated Gsh-2, is described. Analysis of cDNA sequence, including the full open reading frame, reveals an encoded homeodomain that is surprisingly similar to those of the Antennapedia-type clustered Hox genes. In addition, the encoded protein includes polyhistidine and polyalanine tracts, as observed for several(More)
We show that the Cartesian product Za x Zb of two directed cycles is hypo-Hamiltonian (Hamiltonian) if and only if there is a pair of relatively prime positive integers m and n with ma + nb = ab-1 (ma + nb = ab). The result for hypo-Hamiltonian is new; that for Hamiltonian is known. These are special cases of the fact that there is a simple circuit of(More)
Mice with targeted disruptions in Hox genes have been generated to evaluate the role of the Hox complex in determining the mammalian body plan. This complex of 38 genes encodes transcription factors that specify regional information along the embryonic axes. Early in vertebrate evolution an ancestral complex shared with invertebrates was duplicated twice to(More)
Vertebrates develop distinct asymmetries along the left-right axis, which are consistently aligned with the anteroposterior and dorsoventral axes. The mechanisms that direct this handed development of left-right asymmetries have been elusive, but recent studies of mutations that affect left-right development have shed light on the molecules involved. One(More)
We obtain a characterization of the Hamilton paths in the cartesian product Z x Zb of two directed cycles. This provides a correspondence between the collection of Hamilton paths in Za x Zb and the set of visible lattice points in the triangle with vertices (0,O) , (0,a) , and (b,0). We use this correspondence to show there is a Hamilton circuit in the(More)