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A R Campos

Publications and source records attributed to A R Campos.

8 recordsLinked to original sources
PubMed1992

Survival of photoreceptor neurons in the compound eye of Drosophila depends on connections with the optic ganglia.

The importance of retinal innervation for the normal development of the optic ganglia in Drosophila is well documented. However, little is known about retrograde effects of the optic lobe on the adult photoreceptor cells (R-cells). We addressed this question by examining the survival of R-cells in mutant flies where R-cells do not connect to the brain. Although imaginal R-cells develop normally in the absence of connections to the optic lobes, we find that their continued survival requires these connections. Genetic mosaic studies with the disconnected (disco) mutation demonstrate that survival of R-cells does not depend on the genotype of the eye, but is correlated with the presence of connections to the optic ganglia. These results suggest the existence of retrograde interactions in the Drosophila visual system reminiscent of trophic interactions found in vertebrates.

Animals↗
PubMed1991

Isolation and characterization of the disconnected gene of Drosophila melanogaster.

Mutations in the disco (disconnected) gene prevent the establishment of stable connections between the larval optic nerves, the Bolwig's nerves, and their target cells in the brain during embryonic development. The failure of this initial connection is associated with aberrant development of the optic lobes which are largely degenerate in the mutant adult fly. In order to understand the role of disco in establishing this connection, we isolated and characterized the disco gene. A 22 kb DNA fragment can completely rescue the mutant phenotype. A single transcript, 2.9 kb in length, is found in this region and is expressed throughout development of the fly. We determined the nucleotide sequence of the disco gene to be unique when compared with sequences in a number of databases. The predicted amino acid sequence contains a region with similarity to the consensus established for the zinc finger motif. Mobilization of a P-element inserted near the gene resulted in the deletion of the 5' end of the gene and produced flies indistinguishable from those carrying the disco allele.

Amino Acid Sequence↗
PubMed1988

The elav gene product of Drosophila, required in neurons, has three RNP consensus motifs.

A sequence of developmental events transforms neurons from their immature state to their mature, terminally differentiated state. The elav locus is one of the first examples of a gene that is expressed in neurons early during this developmental sequence. This gene has been shown to be required for the proper development of young neurons and for the maintenance of mature neurons. DNA sequence data presented in this report suggest that the elav gene product is an RNA binding protein, based on the presence of RNP (ribonucleoprotein) consensus sequences. This leads to the proposal that this protein is involved in the RNA metabolism of neurons.

Amino Acid Sequence↗
PubMed1987

Molecular analysis of the locus elav in Drosophila melanogaster: a gene whose embryonic expression is neural specific.

The embryonic lethal abnormal visual system (elav) locus in Drosophila melanogaster, a vital gene mapping within the 1B5-1B9 region of the X-chromosome has been cloned and analysed. Previous developmental analyses have shown that in addition to the embryonic requirement there is a post-embryonic requirement for elav function in the cells of the visual system. A DNA segment containing elav+ function was defined through germ line transformation experiments. This region encodes three embryonic poly(A)+ RNAs and two adult transcripts which are preferentially expressed in the head. In situ hybridization experiments clearly demonstrate that the embryonic expression of elav is restricted to the nervous system.

Animals↗
PubMed1985

Mutant alleles at the locus elav in Drosophila melanogaster lead to nervous system defects. A developmental-genetic analysis.

We report a developmental and genetic analysis of the X-linked vital locus l(1)EC7 in Drosophila melanogaster. The locus maps in the salivary band region 1B4-5 to 1B8-9, a part of the X chromosome previously shown to be essential for normal neural development. Certain mutant alleles at the locus can cause embryonic lethality, indicating that the function provided by the gene is essential during embryogenesis. A developmental analysis of gynandromorphic genetic mosaics shows that: (1) the gene function is autonomously essential in the eye; (2) the gene function is essential for normal development of the optic lobes; and (3) the gene function is not necessary in most major imaginal-disc cell derivatives with the exception of the eye disc. Conclusions from the developmental analysis of a temperature sensitive allele are consistent with those from the mosaic analysis. The embryonic lethality caused by the mutant alleles and abnormalities observed in the genetic mosaics have led us to rename the locus l(1)EC7 to elav (embryonic lethal, abnormal visual system).

Alleles↗
PubMed1982

Differential staining of the X-chromosome during meiosis of orthoptera by a silver impregnation procedure.

Differential staining of the X chromosome of Orthoptera, which normally cannot be distinguished from the autosomes during the more condensed stages of meiosis, has been achieved by a silver impregnation procedure involving a pretreatment with 2 x SSC at 60 degrees C. The results suggest that the saline citrate solution preferentially extracts proteins from the X chromosome. This method may be useful for distinguishing chromosome regions composed of facultative heterochromatin in Orthoptera.

Animals↗
PubMed1976

Human schistosomiasis: Schistosoma mansoni antigen detection in renal glomeruli.

Twelve kidney, five biopsy and seven necropsy specimens, all from schistosomiasis mansoni patients were studied by light and immunoflurescent microscopy in an attempt to detect antigen in the glomerular walls. Deposits of IgM, IgG,I gA, IgE, complement C3 and fibrinogen were observered in most cases. Antigen was successfully detected in two cases(one biopsy and one necropsy specimen), both exhibiting proliferative glomerulonephritis. The only clinical manifestation was a slight proteinuria. IgG antibodies eluted from the sutopsy kidney homogenates showed specific binding mostly to Schistosoma mansoni gut, thus spggesting that the fixed antibodies (eluates) are, at least partially, consituted by antibodies similar to the anti-circulating antigen. These data reinfroce the hypothesis that renal injury in schistosomiasis is mediated through an immune complex disease.

Adolescent↗