RESUMO
The Drosophila fruitless (fru) gene product Fru has been postulated to be a neural sex-determination factor that directs the development of at least two male-specific characteristics, namely courtship behaviour and formation of the muscle of Lawrence (MOL). The fru gene encodes a putative transcription factor with a BTB domain and two zinc-finger motifs, and with consensus Tra-binding sequences. The binding of Tra to these sequences results in sex-specific alternative splicing of the fru mRNA, leading to production of the 'male-type' or 'female-type' Fru protein. We show here that the Fru protein is not detected in the female central nervous system (CNS), despite the similar level of expression of fru mRNA in both male and female CNS. As ectopic expression of both the 'male-type' (with the sequence for the amino-terminal extension) and 'female-type' (without the sequence for the amino-terminal extension) fru cDNA can induce formation of the MOL in females, the presence or absence of the Fru protein, and not its sex-specific structure, seems to be responsible for the sexually dimorphic actions of the fru gene.
Assuntos
Proteínas de Drosophila , Drosophila melanogaster/genética , Expressão Gênica , Músculos/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Caracteres Sexuais , Diferenciação Sexual/genética , Fatores de Transcrição/metabolismo , Alelos , Sequência de Aminoácidos , Animais , Animais Geneticamente Modificados , Sistema Nervoso Central/citologia , Sistema Nervoso Central/crescimento & desenvolvimento , Sistema Nervoso Central/metabolismo , Clonagem Molecular , Drosophila melanogaster/citologia , Drosophila melanogaster/crescimento & desenvolvimento , Drosophila melanogaster/metabolismo , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Genes Reporter/genética , Imuno-Histoquímica , Hibridização In Situ , Proteínas de Insetos/química , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Masculino , Dados de Sequência Molecular , Desenvolvimento Muscular , Músculos/citologia , Proteínas do Tecido Nervoso/biossíntese , Proteínas do Tecido Nervoso/química , Proteínas do Tecido Nervoso/genética , Neurônios/metabolismo , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Regiões Promotoras Genéticas/genética , Ligação Proteica , Biossíntese de Proteínas , Pupa/citologia , Pupa/genética , Pupa/crescimento & desenvolvimento , Pupa/metabolismo , RNA Mensageiro/análise , RNA Mensageiro/genética , Ribonucleoproteínas/genética , Ribonucleoproteínas/metabolismo , Fatores de Transcrição/biossíntese , Fatores de Transcrição/química , Fatores de Transcrição/genética , TransfecçãoRESUMO
Mutations in the spin gene are characterized by an extraordinarily strong rejection behavior of female flies in response to male courtship. They are also accompanied by decreases in the viability, adult life span, and oviposition rate of the flies. In spin mutants, some oocytes and adult neural cells undergo degeneration, which is preceded by reductions in programmed cell death of nurse cells in ovaries and of neurons in the pupal nervous system, respectively. The central nervous system (CNS) of spin mutant flies accumulates autofluorescent lipopigments with characteristics similar to those of lipofuscin. The spin locus generates at least five different transcripts, with only two of these being able to rescue the spin behavioral phenotype; each encodes a protein with multiple membrane-spanning domains that are expressed in both the surface glial cells in the CNS and the follicle cells in the ovaries. Orthologs of the spin gene have also been identified in a number of species from nematodes to humans. Analysis of the spin mutant will give us new insights into neurodegenerative diseases and aging.
Assuntos
Apoptose , Sistema Nervoso Central/patologia , Proteínas de Drosophila , Drosophila melanogaster/fisiologia , Proteínas de Insetos/fisiologia , Proteínas de Membrana/fisiologia , Sequência de Aminoácidos , Animais , Animais Geneticamente Modificados , Sequência de Bases , Comportamento Animal , Sistema Nervoso Central/metabolismo , DNA Complementar , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Feminino , Humanos , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Lipofuscina/metabolismo , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Dados de Sequência Molecular , Mutagênese , Degeneração Neural , Neuroglia/metabolismo , Folículo Ovariano/metabolismo , Ovário/crescimento & desenvolvimento , FenótipoRESUMO
Bisexual courtship in male Drosophila melanogaster may be induced in some circumstances. These include ectopic expression of the transformer (tra) gene, ectopic expression of the mini-white (mw) gene, and the homozygous presence of mutant alleles of the fruitless (fru) gene. Experiments were performed to determine if ectopic mw and fru, as well as ectopic tra and fru, acted in the same pathway to control courtship. Male flies homozygous for the frusat allele court females little if at all and males at a low level. When homozygous, the frusat allele suppresses the bisexual courtship induced by both ectopic mw and ectopic tra, indicating that the fru wild-type function is necessary for expression of the ectopic mw and ectopic tra effect. This demonstrates that fru shares a pathway controlling courtship behavior with these ectopically expressed genes.