Maf1 is a negative regulator of transcription in Trypanosoma brucei.
RNA polymerase III (Pol III) produces small RNA molecules that play essential roles in mRNA processing and translation. Maf1, originally described as a negative regulator of Pol III transcription, has been studied from yeast to human. Here we characterized Maf1 in the parasitic protozoa Trypanosoma brucei (TbMaf1), representing the first report to analyse Maf1 in an early-diverged eukaryote. While Maf1 is generally encoded by a single-copy gene, the T. brucei genome contains two almost identical TbMaf1 genes. The TbMaf1 protein has the three conserved sequences and is predicted to fold into a globular structure. Unlike in yeast, TbMaf1 localizes to the nucleus in procyclic forms of T. brucei under normal growth conditions. Cell lines that either downregulate or overexpress TbMaf1 were generated, and growth curve analysis with them suggested that TbMaf1 participates in the regulation of cell growth of T. brucei. Nuclear run-on and chromatin immunoprecipitation analyses demonstrated that TbMaf1 represses Pol III transcription of tRNA and U2 snRNA genes by associating with their promoters. Interestingly, 5S rRNA levels do not change after TbMaf1 ablation or overexpression. Notably, our data also revealed that TbMaf1 regulates Pol I transcription of procyclin gene and Pol II transcription of SL RNA genes.
Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Av. De los Barrios 1, Col. Los Reyes Iztacala, Tlalnepantla, Edo. de México, CP, 54090, México.|Departamento de Biomedicina Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 14-740, México, DF, 07360, México.
Gabriela
G
Romero-Meza
Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Av. De los Barrios 1, Col. Los Reyes Iztacala, Tlalnepantla, Edo. de México, CP, 54090, México.
Daniel E
DE
Vélez-Ramírez
Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Av. De los Barrios 1, Col. Los Reyes Iztacala, Tlalnepantla, Edo. de México, CP, 54090, México.
Luis E
LE
Florencio-Martínez
Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Av. De los Barrios 1, Col. Los Reyes Iztacala, Tlalnepantla, Edo. de México, CP, 54090, México.
Fiordaliso C
FC
Román-Carraro
Departamento de Biomedicina Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 14-740, México, DF, 07360, México.
Rebeca
R
Manning-Cela
Departamento de Biomedicina Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 14-740, México, DF, 07360, México.
Rosaura
R
Hernández-Rivas
Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Av. De los Barrios 1, Col. Los Reyes Iztacala, Tlalnepantla, Edo. de México, CP, 54090, México.
Santiago
S
Martínez-Calvillo
D000595:Amino Acid Sequence; D002467:Cell Nucleus / Q000378:metabolism; D047369:Chromatin Immunoprecipitation; D017124:Conserved Sequence; D050977:Maf Transcription Factors / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D009687:Nuclear Proteins / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D017434:Protein Structure, Tertiary; D012318:RNA Polymerase I / Q000378:metabolism; D012319:RNA Polymerase II / Q000378:metabolism; D012320:RNA Polymerase III / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic / Q000502:physiology; D014346:Trypanosoma brucei brucei / Q000235:genetics* / Q000378:metabolism
D050977:Maf Transcription Factors; D009687:Nuclear Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; D012319:RNA Polymerase II; D012318:RNA Polymerase I; D012320:RNA Polymerase III