RESUMEN
Analysis of the subunit polypeptide composition of Fraction 1 proteins gives information on the expression of both nuclear and chloroplast genomes; the large subunits of the protein are coded by chloroplast DNA, whereas the small subunits are coded by nuclear DNA. Fraction 1 protein isolated from the leaves of parasexual hybrid plants derived from the fusion of protoplasts of Nicotiana glauca and N. langsdorffii contains the small subunit polypeptides of both parent species and the large subunit polypeptides of only N. glauca. Fraction 1 protein isolated from the leaves of a hybrid plant obtained after the uptake of chloroplasts of N. suaveolens by protoplasts of white tissue of a variegating mutant of N. tabacum contains the large subunit polypeptides of both N. suaveolens and N. tabacum, as well as the small subunit polypeptides of both these species.
RESUMEN
The cDNA coding for a novel protein kinase from soybean (Glycine max L.), named GmPK6, was sequenced. The primary sequence of GmPK6 consists of 462 amino acids with an N-terminal sequence similar to the central region of Xenopus U1 snRNP 70K protein, and a C-terminal kinase domain representing structural mosaicism with features diagnostic of both protein serine/threonine and tyrosine kinases in eukaryotic organisms. The GmPK6 gene is expressed as 2.5 kb transcript in a variety of tissues.
Asunto(s)
Glycine max/enzimología , Familia de Multigenes , Proteínas Quinasas/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Southern Blotting , Clonación Molecular , ADN/genética , ADN/aislamiento & purificación , Datos de Secuencia Molecular , Homología de Secuencia de Aminoácido , Programas Informáticos , Glycine max/genética , XenopusRESUMEN
There are two inverted repeat nucleotide (nt) sequences, each capable of forming a stem-loop structure (sls) at the 3' end of the tobacco Rubisco large subunit mRNA (rbcL). The smaller sls is followed by a larger sls. The in vivo functions of the 3' sls of the rbcL mRNA were characterized using the Escherichia coli system. S 1 mapping of the rbcL transcripts synthesized in E. coli revealed that the 3' end of a major transcript in the bacterial cell is almost identical to the 3' end of authentic chloroplast (cp) rbcL mRNA. This native 3' end is located 4 nt downstream from the larger sls for the cp mRNA and 6 nt for the bacterial transcript, respectively. Deletion experiments show that the larger sls is essential for producing the native 3' end of rbcL mRNA in E. coli. The sls do not function as an efficient transcription terminator but can stabilize upstream mRNA segments in vivo.
Asunto(s)
Cloroplastos/química , Nicotiana/genética , Plantas Tóxicas , ARN Mensajero/biosíntesis , Secuencia de Bases , Northern Blotting , Deleción Cromosómica , Mapeo Cromosómico , Escherichia coli/genética , Datos de Secuencia Molecular , Polimorfismo de Longitud del Fragmento de Restricción , Secuencias Repetitivas de Ácidos Nucleicos , Homología de Secuencia de Ácido Nucleico , Regiones Terminadoras Genéticas , Transcripción GenéticaRESUMEN
The galK-expression plasmid vector system pKO1 has been used to clone Nicotiana chloroplast (ct) promoters that function in Escherichia coli. The randomly cloned promoter-containing restriction fragments have been located on the ct genome and originate both from those regions encoding ribosomal and transfer RNAs and from locations elsewhere on the ct genome. The results provide the first demonstration that sequences which function as prokaryotic promoters exist in the ct genome.
Asunto(s)
Cloroplastos/análisis , Escherichia coli/genética , Nicotiana/genética , Plantas Tóxicas , Regiones Promotoras Genéticas , Clonación Molecular , ADN Recombinante/fisiología , ADN Ribosómico/genética , Vectores Genéticos , Plásmidos , ARN de Transferencia/genética , Especificidad de la EspecieRESUMEN
Multiple genes have been found to encode families of protein kinases in animals and yeasts. Little is known of the diversity of protein kinase families in plants. We have used the polymerase chain reaction to identify members of protein kinase gene family in rice. We have cloned eight partial cDNA sequences from which deduced amino acid sequences contained conserved sequences or amino acid residues characteristic of catalytic domains of eukaryotic protein serine/threonine kinases. Our results suggest that there is great complexity in the protein kinase gene family in plants and that protein phophorylation may play an as important role in plants as in in other eukaryotes.
Asunto(s)
Variación Genética , Oryza/enzimología , Proteínas Quinasas/genética , Secuencia de Aminoácidos , Secuencia de Bases , Clonación Molecular , ADN , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa , Proteínas Quinasas/metabolismo , Alineación de SecuenciaRESUMEN
A series of nested N-terminal deletions were made on the full-length (wt) and C-terminal deleted (Cdel) 1-aminocyclopropane-1-carboxylate synthase cDNAs. These wt and mutant ACC synthases were over-expressed in a heterologous E. coli expression system. It was found that removal of an amino acid region (residues 2-12) from the non-conserved N-termini of wt and Cdel ACC synthases led to a slight increase in both in vivo ACC production and in vitro ACC synthase activity. Further deletion of 11 amino acids through Glu-23 from the N-termini of both wt and Cdel ACC synthases resulted in a substantial reduction in both in vivo ACC production and in vitro enzyme activity. Deletion of an amino acid region, residues 3 through 27, from the N-terminus of ACC synthase abolished enzyme activity completely. Kinetic analysis of a highly purified double-deletion mutant (NCdel-1) of ACC synthase demonstrated that the Km of this mutant is 42 microM, which is much smaller than that of the corresponding Cdel (280 microM) and closer to that of wt (22 microM) reported previously, suggesting a clear effect of the non-conserved N-terminal region on its ACC synthase function.
Asunto(s)
Liasas/genética , Liasas/metabolismo , Eliminación de Secuencia , Secuencia de Aminoácidos , Secuencia de Bases , Escherichia coli/genética , Cinética , Liasas/química , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , S-Adenosilmetionina/metabolismo , Relación Estructura-ActividadRESUMEN
The RNA-dependent RNA polymerases (RdRp) of cucumber mosaic virus (CMV) and peanut stunt virus (PSV), members of the cucumovirus group, have been purified from virus infected plants and were used to study RNA synthesis in vitro using different viral RNAs, two cucumoviral satellites, and chimeric satellite cDNA clone transcripts as templates. The results show that solubilized RdRp preparations of CMV and PSV have a high degree of template dependency and catalyze (-) strand synthesis of the homologous cucumoviral RNAs with greater efficiency than the RNAs of heterologous cucumoviruses, although the PSV RdRp exhibits a lesser specificity than the CMV RdRp. On the other hand, both (-) and (+) strands of the satellite RNAs of CMV and PSV are synthesized by their homologous but not by the heterologous viral RdRps, indicating that recognition of satellites by the viral RdRp determines their replicative dependence upon specific helper viruses. Cucumoviral RdRp reactions using chimeric satellite transcripts suggest that the promoter structure for the satellite (-) strand synthesis resides in regions harboring the 3' termini of the two satellites.
Asunto(s)
Cucumovirus/enzimología , ARN Viral/biosíntesis , ARN Polimerasa Dependiente del ARN/metabolismo , ARN/biosíntesis , Secuencia de Bases , Cartilla de ADN , Datos de Secuencia Molecular , Satélite de ARN , Moldes GenéticosAsunto(s)
Clorofila/aislamiento & purificación , Cloroplastos/análisis , Proteínas de Plantas/aislamiento & purificación , Acrilamidas , Cloroplastos/metabolismo , Densitometría , Detergentes , Electroforesis , Métodos , Fotosíntesis , Células Vegetales , Extractos Vegetales , Plantas Tóxicas , Espectrofotometría , Ácidos Sulfúricos , Nicotiana/citologíaAsunto(s)
Núcleo Celular , Cloroplastos , ADN , Núcleo Celular/análisis , Centrifugación por Gradiente de Densidad , Fenómenos Químicos , Química Física , Clorofila/análisis , Cloroplastos/análisis , Cloroplastos/microbiología , ADN/análisis , ADN/aislamiento & purificación , ADN Bacteriano , Densitometría , Métodos , Desnaturalización de Ácido Nucleico , Nucleótidos/análisis , Células Vegetales , Plantas/análisis , Temperatura , UltracentrifugaciónAsunto(s)
Núcleo Celular/análisis , Cloroplastos/análisis , ADN/análisis , Plantas/análisis , Fraccionamiento Celular , Centrifugación por Gradiente de Densidad , Clorofila/análisis , Cloroplastos/microbiología , ADN/aislamiento & purificación , ADN Bacteriano/análisis , Estabilidad de Medicamentos , Calor , Micrococcus/análisis , Desnaturalización de Ácido Nucleico , Células Vegetales , Polímeros , Semillas/análisis , Espectrofotometría , Factores de Tiempo , Ultracentrifugación , Rayos Ultravioleta , VibraciónAsunto(s)
Proteínas de Plantas , Secuencia de Aminoácidos , Aminoácidos/análisis , Radioisótopos de Carbono , Cloroplastos/metabolismo , Cromatografía en Gel , Cristalización , ADN/metabolismo , Electroforesis en Gel de Poliacrilamida , Concentración de Iones de Hidrógeno , Focalización Isoeléctrica , Sustancias Macromoleculares , Peso Molecular , Fenotipo , Plantas/metabolismo , Plantas Tóxicas , Unión Proteica , Dodecil Sulfato de Sodio , Espectrofotometría Ultravioleta , Nicotiana/metabolismo , Transcripción Genética , Tripsina , UreaAsunto(s)
Cianobacterias , ADN , Bacteriófagos , Núcleo Celular , Centrifugación por Gradiente de Densidad , Cloroplastos/citología , Nucleótidos de Citosina/análisis , ADN/análisis , ADN Bacteriano , ADN Viral , Densitometría , Nucleótidos de Guanina/análisis , Calor , Mitocondrias , Desnaturalización de Ácido Nucleico , Especificidad de la Especie , Espectrofotometría , Factores de Tiempo , Rayos UltravioletaRESUMEN
A physical map containing six restriction sites of the Nicotiana tabacum chloroplast genome, together with the BamHI maps of N. tabacum, N. otophora and N. knightiana, and the SmaI maps of N. acuminata, N. plumbaginifolia, N. langsdorffii, N. otophora, N. tabacum, N. tomentosiformis and N. knightiana was constructed. In Nicotiana chloroplast genomes, the most frequently observed variations are point mutations. Deletions are also detected. Most of the observed changes are confined to one area of the large single copy region, which is designated as the "hot spot". Based on the evidence obtained from Nicotiana chloroplast genomes, an origin of the inverted repeats in this genus is proposed. We suggest that the inverted repeats represent a vestige of what were once two identical, complete chloroplast genomes joined together in a head-to-head and tail-to-tail fashion, and that deletions generated the current chloroplast genome organization.
RESUMEN
Using the existing restriction map and probes from wheat and pea ct-DNA, seven protein genes have been localized in the chloroplast genome of N. tabacum. On the clock-like map, the location of each gene is indicated by its time zone: the 15.2 kD polypeptide of the cytochrome b/f complex at 3â¶15, cytochrome f at 4â¶30, LS of RuBPCase at 4â¶50, both ß and É subunits of ATP synthase at or near 5â¶00, proton-translocating subunit of ATP synthase at 8â¶20, α subunit of ATP synthase at 8â¶40 and the 32 kD protein at 9â¶30. The genome organization of Nicotiana chloroplast DNA is similar to spinach.
RESUMEN
This survey compiles 60 chloroplast promoter sequences from higher plants published to date and compares them with these sequences from procaryotic systems. The current evidence demonstrates that structurally defined chloroplast promoters are, in most cases, functionally active in initiating gene expression in chloroplasts.
Asunto(s)
Cloroplastos/metabolismo , Plantas/genética , Regiones Promotoras Genéticas , Secuencia de Bases , Especificidad de la EspecieRESUMEN
Crystalline fraction 1 protein, obtained from four species of Nicotiana, have identical polypeptide compositions and isoelectric points. However, the tryptic peptide map of the large subunit of this protein from N. knightiana and N. paniculata differs from that of N. tomentosa and N. tomentosiformis. Since the large subunits of fraction 1 protein are coded by chloroplast DNA, the difference in their primary structure reflects the structural changes of the chloroplast genes containing the coding information. This indicates that the rate of mutation of chloroplast DNA seems to be higher than predicated from the analysis of isoelectric points of this protein.
RESUMEN
As a first step to investigate the functions of homeobox genes in tobacco genetic tumorigenesis, we have used polymerase chain reaction to identify Hot (Homeobox in tobacco) genes that are expressed in tobacco genetic tumors. Five Hot genes that are actively expressed in tobacco genetic tumors are identified. Particularly, Hot1 is profoundly abundant in tumorous tissues, suggesting that it acts as a positive regulator of cell growth and differentiation during genetic tumorigenesis.
Asunto(s)
Genes Homeobox , Genes de Plantas , Nicotiana/genética , Nicotiana/metabolismo , Plantas Tóxicas , Secuencia de Aminoácidos , Secuencia de Bases , Northern Blotting , Southern Blotting , Secuencia Conservada , ADN/aislamiento & purificación , ADN/metabolismo , Cartilla de ADN , Expresión Génica , Datos de Secuencia Molecular , Tumores de Planta , Reacción en Cadena de la Polimerasa/métodos , ARN/metabolismo , Homología de Secuencia de AminoácidoRESUMEN
The involvement of phytochrome in the control of the levels of RNA transcribed from maize plastid and nuclear genes was examined. The effects of illumination with red light, far-red light, or red light followed by far-red light on relative amounts of RNAs complementary to maize plastid genes for the large subunit of ribulose bisphosphate carboxylase (RuBPCase); the 32-kilodalton thylakoid membrane triazine herbicide binding B protein of photosystem II; the alpha, beta, and epsilon subunits of CF(1); subunit III (proton-translocating) of CF(0); the reaction center proteins A1 and A2 of photosystem I; two other light-induced genes for membrane proteins of photosystem II (ORFs 353 and 473); and one gene for an unidentified membrane protein (UORF 443) were measured by hybridization of labeled DNA probes to samples of leaf RNA. Transcripts of two nuclear-encoded genes, the genes for the small subunit of RuBPCase and the light-harvesting chlorophyll a/b binding protein, were studied in the same way. The levels of RNA complementary to all of these light-induced genes were significantly increased within 3 to 6 hours after brief illumination with red light. The stimulatory effects of red light were largely reversed by subsequent illumination with far-red light. It is concluded that phytochrome controls increases in the levels of mRNAs complementary to certain plastid and nuclear genes in dark-grown maize seedlings.