RESUMEN
Two cryptic plasmids of two environmental strains of the soil Bacillus mycoides were cloned and sequenced. They are of a small size (3377 and 3476 bp) and carry regions homologous to double- and single-strand origins of replication of rolling-circle replication modules. In addition, both plasmids have ORFs with homologies with Mob and Rep proteins, in the same relative position and orientation. While dso- and sso-like sequences are similar in pBMY1 and pBMYdx, the putative Mob and Rep proteins are not homologous between the two but show similarity with Mob and Rep proteins of different bacterial plasmids.
Asunto(s)
Bacillus/genética , ADN Bacteriano/genética , Bacterias Grampositivas/genética , Plásmidos/genética , Microbiología del Suelo , Bacillus/clasificación , Bacillus/aislamiento & purificación , Secuencia de Bases , Datos de Secuencia Molecular , Sistemas de Lectura Abierta , Plásmidos/aislamiento & purificación , Análisis de Secuencia de ADN , Homología de Secuencia de Ácido NucleicoRESUMEN
The genes coding for the ribosomal proteins (rp genes) L14 and L1 in the toad Xenopus laevis are contacted in the first exon by the frog protein, FIII/YY1, homolog of the human zinc-finger protein YY1, acting as repressor, activator and initiator of transcription. To investigate the functional significance of FIII/YY1 in the context of the two rp genes, the L14 region at nucleotide positions -105 to +44, including all of the first exon was linked to the chloramphenicol acetyltransferase (CAT) reporter gene; constructs with wild-type and mutated sites for FIII/YY1 were injected into nuclei of stage V-VI oocytes and analyzed for CAT activity. The same procedure was followed for constructs made with L1 sequences at nucleotide positions -17 to +1567. Mutations in the sites for FIII/YY1 did not change reporter activity, nor did overexpression of FIII/YY1 in the oocytes prior to injection with L1 and L14 constructs. Since oocytes are non-dividing cells, transfections were made of Xenopus kidney cells in culture with the same constructs and the results obtained in oocytes confirmed.
Asunto(s)
Proteínas de Unión al ADN/metabolismo , Exones , Regiones Promotoras Genéticas , Proteínas Ribosómicas/genética , Factores de Transcripción/metabolismo , Animales , Sitios de Unión , Factores de Unión al ADN Específico de las Células Eritroides , Plásmidos , Proteínas de Xenopus , Xenopus laevis , Factor de Transcripción YY1RESUMEN
The cDNA coding for the Xenopus laevis homolog of the transcriptional activator/repressor protein delta/YY1 was isolated from a lambda gt11 oocyte cDNA library. The deduced aminoacid sequence shows that the four zinc fingers of the DNA binding domain are 99% conserved when compared to the mouse (delta) and 95% to the human (YY1) proteins, while differences are found in the N-terminal region. In particular, the long run of consecutive glycines and histidines of delta and YY1 is missing. The protein, named FIII/YY1, was overexpressed into Xenopus oocytes from the cDNA under direction of the L14 rp-promoter and found to share antigenic and DNA-binding properties with the oocyte endogenous protein binding to the first exon of the X.laevis ribosomal protein genes (rp-genes) L1 and L14.