RESUMO
The chaperonins are evolutionarily conserved essential cellular proteins that help folding newly synthesized or translocated proteins, spending ATP. We present here the molecular analysis of the hsp60 gene promoter region and of two Drosophila hsp60 ethyl methane sulfonate embryonic lethal alleles that have an identical phenotype. No heat shock element sequences were found in the 5' region, supporting previous data (Kozlova, T. et al., 1997) which suggests that mitochondrial Drosophila melanogaster HSP60.1 is not heat inducible. By sequencing the lethal allele's entire open reading frame (ORF), we found a C-T transition in the hsp60F409 allele that produces a serine to leucine change, apparently distorting the protein equatorial domain structure. No changes were found in the hsp60G93 ORF. However, an analysis of the heterogeneous nuclear RNA levels showed a reduction of the hsp60 transcript in hsp60G93 flies as compared to the wild-type. These data suggest that although the defects in the hsp60 gene produced by these alleles are at different levels, both behave as null mutations.
Assuntos
Chaperonina 60/genética , Drosophila melanogaster/genética , Genes de Insetos , Alelos , Animais , Sequência de Bases , Chaperonina 60/química , Clonagem Molecular , DNA Complementar/genética , Drosophila melanogaster/metabolismo , Metanossulfonato de Etila , Genes Letais , Modelos Moleculares , Dados de Sequência Molecular , Mutagênicos , Fases de Leitura Aberta , Mutação Puntual , Regiões Promotoras Genéticas , Conformação Proteica , RNA Mensageiro/genética , RNA Mensageiro/metabolismoRESUMO
Clay minerals are considered important to chemical evolution processes due to their properties, ancient origin, and wide distribution. To extend the knowledge of their role in the prebiotic epoch, the adsorption sites of adenine, adenosine, AMP, ADP, ATP, Poly A, uracil, uridine, UMP, UDP, UTP and Poly U on sodium montmorillonite are investigated. X-ray diffraction, ultraviolet and infrared spectroscopy studies indicate that these molecules distribute into the interlamellar channel and the edge of the clay crystals. Monomers are adsorbed predominantly in the interlamellar channel, whereas polymers adsorb along the crystal edges. Such behavior is discussed mainly in terms of bulk pH, pK(a) of the adsorbate, and Van der Waals interactions.
Assuntos
Adenina/química , Bentonita/química , Evolução Química , Uracila/química , AdsorçãoRESUMO
Abstract. The Drosophila genome contains a single orthologue of mammalian puromycin-sensitive aminopeptidases, dPsa. Even though dPsa was expressed in many tissues during development, animals lacking dPsa activity were viable. Ubiquitous overexpression of dPsa during embryonic or larval development resulted in lethality and overexpression in isolated tissues during development resulted in localized lesions. These results suggest that even though dPsa function was not essential for viability, dPsa expression must be tightly regulated for normal development. By screening the Drosophila genome we found 43 predicted aminopeptidases and generated a phylogenetic tree of aminopeptidases related to dPsa by sequence. We discuss possible functions of dPsa and the idea that other Drosophila aminopeptidases might perform redundant functions with dPsa for regulating protein turnover.