Gerard L. Campbell

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We report the identification of RK2, a glial-specific homeodomain protein. RK2 is localized to the nucleus of virtually all embryonic and imaginal glial cells, with the exception of midline glia. Embryos mutant for the gene encoding RK2 are embryonic lethal but normal for early gliogenesis (birth, initial divisions and migration of glia) and axonogenesis(More)
Dpp, a TGFbeta, organizes pattern in the Drosophila wing by acting as a graded morphogen, activating different targets above distinct threshold concentrations. Like other TGFbetas, Dpp appears to induce transcription directly via activation of a SMAD, Mad. However, here we demonstrate that Dpp can also control gene expression indirectly by downregulating(More)
The wingless (wg) and decapentaplegic (dpp) genes of Drosophila encode homologs of secreted growth factors and are required for the correct patterning of the appendages. We show that the presumptive tips of both the leg and wing, the distal extreme of the proximodistal axis, are characterized by the close association of cells expressing wg, dpp, and the(More)
In the leg and wing imaginal discs of Drosophila, the expression domains of the homeobox genes aristaless (al) and Distal-less (Dll) are defined by the secreted signaling molecules Wingless (Wg) and Decapentaplegic (Dpp). Here, the roles played by al and Dll in patterning the legs and wings have been investigated through loss of function studies. In the(More)
Cell fate decisions in the early Drosophila wing disc assign cells to compartments (anterior or posterior and dorsal or ventral) and distinguish the future wing from the body wall (notum). Here we show that EGF-receptor (EGFR) signaling stimulated by its ligand, Vein, has a fundamental role in regulating two of these cell fate choices: (1) Vn/EGFR signaling(More)
The distal region of the Drosophila leg, the tarsus, is divided into five segments (ta I-V) and terminates in the pretarsus, which is characterized by a pair of claws. Several homeobox genes are expressed in distinct regions of the tarsus, including aristaless (al) and lim1 in the pretarsus, Bar (B) in ta IV and V, and apterous (ap) in ta IV. This pattern(More)
The heterophilic CD2-CD58 adhesion interface contains interdigitating residues that impart high specificity and rapid binding kinetics. To define the hot spot of this counter-receptor interaction, we characterized CD2 adhesion domain variants harboring a single mutation of the central Tyr86 or of each amino acid residue forming a salt link/hydrogen bond.(More)
The transcription factor Brinker (Brk) represses gene expression in the Drosophila wing imaginal disc, where it is expressed in symmetrical lateral-to-medial gradients, a pattern that is established by inverse gradients of the TGF-beta, Dpp, which is in turn transduced into graded phosphorylated Mad (pMad, an R-Smad). pMad is part of a complex which(More)
The human homologue of the Drosophila discs large tumor suppressor protein (hDlg), a member of the membrane-associated guanylate kinase (MAGUK) superfamily, interacts with K(+) channels, N-methyl-d-aspartate receptors, calcium ATPase, adenomatous polyposis coli, and PTEN tumor suppressor proteins, and several viral oncoproteins through its PDZ domains.(More)