A carbohydrate epitope expressed uniquely on the cell surface of Drosophila neurons is altered in the mutant nac (neurally altered carbohydrate).

Abstract

Antibodies against horseradish peroxidase (anti‐HRP) recognize neural specific cell surface antigens in Drosophila and other insects. The nature of these antigens was investigated in Drosophila and found to include a complex set of developmentally regulated proteins. Their common epitope appears to be a carbohydrate that shares features with the sugar moiety of pineapple stem bromelain, a plant glycoprotein whose carbohydrate structure has been determined. A mutation was identified that eliminates staining by the antibody in imaginal and adult neural tissue. Tissue specific glycoconjugates, although widespread in the animal kingdom, are little understood. This mutation provides a unique opportunity to address the consequences of altering a neural specific carbohydrate moiety in an otherwise intact and behaving animal. The mutation maps to 84F. A second mutation, contained on the third chromosome balancer, TM3, eliminates anti‐HRP staining in embryos. These mutations appear to be separate genes.

DrosophilaFragile X Mental Retardation Protein and Metabotropic Glutamate Receptor A Convergently Regulate the Synaptic Ratio of Ionotropic Glutamate Receptor Subclasses

“…Qin et al, 2005). Fluorescence intensity was compared with an internal fluorescent signal marking the NMJ synaptic terminal: anti-HRP labels a carbohydrate epitope in the neuronal membrane of NMJ boutons (Katz et al, 1988;Wang et al, 1994;Sun and Salvaterra, 1995). The dfmr1 null and w 1118 genetic background control [wild-type (WT)] animals were processed simultaneously and imaged using identical microscope settings.…”

The Drosophila Neurally Altered Carbohydrate Mutant Has a Defective Golgi GDP-fucose Transporter

“…In this study, we identified a single nucleotide transition (C86T) that produces a leucine for serine substitution at position 29 of the Golgi GDP-fucose transporter encoded by the nac 1 Gfr gene. The mutagen originally used to isolate the nac 1 mutant was ethyl methane sulfonate (33). Mechanistically, ethyl methane sulfonate is expected to produce G/C to A/T transitions (80,81), and this expectation has been confirmed in mutagenesis studies (82)(83)(84).…”

“…The original nac mutant, which was later redesignated nac 1 to distinguish it from other alleles, has a temperature-insensitive loss of the neural HRP epitope associated with other coldsensitive phenotypes expressed at 18°C but not 25°C (33,34). Katz et al (33) cytogenetically mapped the nac 1 mutation to the region between 84F4 and 84F11-12, which includes about 32 genes.…”

“…4, A, B, E, and F), as shown previously (21,33). In order to determine if the Gfr C86T mutation was solely responsible for this change, we generated transgenic Drosophila stocks designed to express the WT Gfr coding sequence in nac 1 embryos using the GAL4/ UAS system (46).…”

An Endogenous Drosophila Receptor for Glycans Bearing α1,3-Linked Core Fucose Residues

“…The pattern of staining of Drosophila embryos with antihorseradish peroxidase antibodies suggests a role for core ␣1,3-linked fucose in the nervous system (31)(32)(33). The ability of CG2958 to serve as an endogenous receptor for glycoproteins bearing core ␣1,3-linked fucose further suggests that this protein might also be expressed in the nervous system.…”