ABSTRACT
In Drosophila, broad complex, tramtrack, bric à brac (BTB)/poxvirus and zinc finger (POZ) transcription factors are essential regulators of development. We searched the Drosophila genome for BTB/POZ-ZF domains and discovered an unknown Drosophila gene, dPLZF, which encodes an orthologue of human PLZF. We then characterized the biological function of the dPLZF via genetic interaction analysis. Ectopic expression of dPLZF in the wing induced extra vein formation during wing development in Drosophila. Genetic interactions between dPLZF and Ras or extracellular signal-regulated kinase (ERK) significantly enhanced the formation of vein cells. On the other hand, loss-of-function mutations in dPLZF resulted in a dramatic suppression of the extra and ectopic vein formation induced by elevated Ras/ERK signaling. Moreover, dPLZF activity upregulated the expression of rhomboid (rho) and spitz, which perform crucial functions in vein cell formation in the developing wing. These results indicate that dPLZF is a transcription factor controlled by the Ras/ERK signaling pathway, which is a prominent regulator of vein cell formation during wing development in Drosophila.
Subject(s)
Drosophila/growth & development , Extracellular Signal-Regulated MAP Kinases/genetics , Genes, ras , Kruppel-Like Transcription Factors/genetics , Kruppel-Like Transcription Factors/metabolism , Transcription Factors/genetics , Wings, Animal/growth & development , Animals , Animals, Genetically Modified , Avipoxvirus/genetics , Avipoxvirus/metabolism , Drosophila/genetics , Drosophila/metabolism , Drosophila Proteins/genetics , Drosophila Proteins/metabolism , Epidermal Growth Factor/genetics , Epidermal Growth Factor/metabolism , Extracellular Signal-Regulated MAP Kinases/metabolism , Humans , Membrane Proteins/genetics , Membrane Proteins/metabolism , Mutation , Promyelocytic Leukemia Zinc Finger Protein , Protein Structure, Tertiary , Signal Transduction/genetics , Transcription Factors/metabolism , Wings, Animal/metabolism , Zinc Fingers/geneticsABSTRACT
The aim of this study was to evaluate HCV-cytotoxic T lymphocyte response from PBMC in bulk CTL assays and in CTL precursor analyses using in vitro stimulation with canarypox virus (ALVAC) expressing HCV-capsid/E1/E2/NS2/NS3 antigens. Canarypox virus is naturally host-range restricted and does not replicate or cause cytopathology on mammalian cells. PBMC were obtained from four chimpanzees with chronic hepatitis C infection and one uninfected chimpanzee. CTL from bulk culture of PBMC and CTL precursor frequencies were found in three of the four chronically infected chimpanzees using ALVAC in vitro stimulation. No CTL response was detected in PBMC from the uninfected chimpanzee. The precursor frequencies of CTL specific for capsid, NS2 and NS3 proteins ranged between 1/2663 and 1/27202. No correlation was observed between percent cytolysis in bulk culture and CTL precursor frequencies. This method may prove useful in assessing the correlation between HCV-CTL response and virological or histological status.
