RESUMO
Suppressor of fused (Sufu) is a negative regulator of the Hedgehog pathway both in Drosophila and vertebrates. Here, we report the genomic organization of the mouse Sufu gene (mSufu). This gene comprises 11 exons spanning more than 30 kb and encodes a protein with a putative PEST sequence. DNA-consensus sequences recognized by basic helix-loop-helix (bHLH) proteins, referred to as E-box motifs, are found in the 5' flanking region. Analysis by single-strand conformation polymorphism and radiation hybrid positioned the Sufu locus to the distal end of mouse Chr 19 between D19Mit102 and D19Mit9, near the Fgf8 and dactylin genes. Mouse Sufu is expressed in various tissues, particularly in the nervous system, ectoderm, and limbs, throughout the developing embryo. Sufu binds with all three Gli proteins, with different affinities. This report, in conjunction with recent studies, points out the importance of Sufu in mouse embryonic development.
Assuntos
Genes/genética , Proteínas Repressoras/genética , Processamento Alternativo , Animais , Sequência de Bases , Mapeamento Cromossômico , DNA/química , DNA/genética , Embrião de Mamíferos/metabolismo , Éxons , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Glutationa Transferase/genética , Glutationa Transferase/metabolismo , Hibridização In Situ , Íntrons , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Dados de Sequência Molecular , Muridae , Proteínas Oncogênicas/genética , Proteínas Oncogênicas/metabolismo , Ligação Proteica , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Proteínas Repressoras/metabolismo , Análise de Sequência de DNA , Transativadores , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Técnicas do Sistema de Duplo-Híbrido , Proteína GLI1 em Dedos de ZincoRESUMO
The Suppressor of fused [Su(fu)] gene of Drosophila melanogaster encodes a protein containing a PEST sequence [sequence enriched in proline (P), glutamic acid (E), serine (S) and threonine (T)] which acts as an antagonist to the serine-threonine kinase Fused in Hedgehog (Hh) signal transduction during embryogenesis. The Su(fu) gene isolated from a distantly related Drosophila species, D. virilis, shows significantly high homology throughout its protein sequence with its D. melanogaster counterpart. We show that these two Drosophila homologs of Su(fu) are functionally interchangeable in enhancing the fused phenotype. We have also isolated mammalian homologs of Su(fu). The absence of the PEST sequence in the mammalian Su(fu) protein suggests a different regulation for this product between fly and vertebrates. Using the yeast two-hybrid method, we show that the murine Su(fu) protein can interact directly with the Fused and Cubitus interruptus proteins, known partners of Su(fu) in Drosophila. These data are discussed in the light of their evolutionary relationships.
Assuntos
Sequência Conservada , Proteínas de Drosophila , Drosophila/embriologia , Proteínas de Insetos/metabolismo , Proteínas Repressoras/fisiologia , Transdução de Sinais/genética , Sequência de Aminoácidos , Animais , Proteínas Hedgehog , Camundongos , Dados de Sequência Molecular , Ligação Proteica , Proteínas Repressoras/química , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Homologia de Sequência de AminoácidosRESUMO
The segment polarity gene fused (fu) is involved in specification of positional information inside embryonic segments in Drosophila melanogaster (Dm). The predicted Fused (Fu) protein contains a serine/threonine kinase domain and a second domain with unknown function. We cloned and sequenced the fu homologous gene from Drosophila virilis (Dv) and made an interspecific DNA sequence comparison to identify regions that have been conserved during evolution. Comparison of the predicted amino acid (aa) sequences reveals two regions of strong homology, one corresponding to the kinase domain (268 aa), the other located in the third exon of the Dm fu gene, suggesting a functional importance for this region. Stretches of significantly conserved sequences are also observed in the 5' and 3' untranslated regions. Weak homology is seen in the intronic sequences although the adjacent exonic sequences are mostly conserved. These findings indicate a high conservation of the predicted Fu protein during the evolution of Drosophila.
Assuntos
Drosophila/genética , Genes de Insetos , Sequência de Aminoácidos , Animais , Sequência de Bases , Evolução Biológica , Clonagem Molecular , Sequência Conservada , DNA/genética , Drosophila/embriologia , Drosophila melanogaster/genética , Éxons , Íntrons , Dados de Sequência Molecular , Mapeamento por Restrição , Homologia de Sequência de Aminoácidos , Especificidade da EspécieRESUMO
The mechanisms which coordinate and regulate secondary vitellogenesis and molting in Orchestia gammarellus have been studied in natural and experimental conditions. The onset of secondary vitellogenesis, requiring a protocerebral factor and a low titer of ecdysteroids, occurs only after normal folliculogenesis. The secondary follicular tissue would secrete vitellogenin stimulating ovarian hormone (VSOH) which stimulates the subepidermal adipose tissue to produce vitellogenin. VSOH and ecdysteroids are indispensable to normal vitellogenin synthesis during secondary vitellogenesis. Moreover, the Y-organ controls vitellogenin entry into the oocytes. In secondary vitellogenesis the ovary would stimulate the secretion of molt inhibiting hormone (MIH) which would act on the epidermis, rendering this tissue unresponsive to the stimulatory action of ecdysterone. The Y-organ and the protocerebrum are involved in the control of the molting processes independently of their action on vitellogenesis.
