Potential regulatory elements in the Trypanosoma cruzi rRNA gene promoter.
The Trypanosoma cruzi rRNA gene promoter was characterized by deletion and point mutation analyses. A core of 89 bp was identified as the minimal region with full promoter activity. This core region is flanked upstream by a control element that stimulates its activity, and downstream by a novel down regulating region of about 200 bp. A point mutation analysis of the transcription start region evidenced 7 contiguous nucleotides where individual substitutions produced in all cases a defective promoter. It is generally accepted that the anciently speciated trypanosomatids lack strict promoters for protein coding genes transcribed by RNA polymerase II. The occurrence of a well structured rRNA gene promoter in these species suggests an early appearance of the RNA polymerase I promoters in the evolution of eukaryotic cells.
Figueroa-Angulo
Elisa
E
Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Apartado Postal 70-228, 04510 México DF, Mexico.
María Cevallos
Ana
A
Zentella
Alejandro
A
López-Villaseñor
Imelda
I
Hernández
Roberto
R
D000818:Animals; D001483:Base Sequence; D017354:Point Mutation; D011401:Promoter Regions, Genetic; D016053:RNA, Protozoan / Q000235:genetics*; D012335:RNA, Ribosomal / Q000235:genetics*; D012045:Regulatory Sequences, Nucleic Acid; D014349:Trypanosoma cruzi / Q000235:genetics*
D016053:RNA, Protozoan; D012335:RNA, Ribosomal