Telomerase RNA plays a major role in the completion of the life cycle in Ustilago maydis and shares conserved domains with other Ustilaginales

Abstract

The RNA subunit of telomerase is an essential component whose primary sequence and length are poorly conserved among eukaryotic organisms. The phytopathogen Ustilago maydis is a dimorphic fungus of the order Ustilaginales. We analyzed several species of Ustilaginales to computationally identify the TElomere RNA (TER) gene ter1. To confirm the identity of the TER gene, we disrupted the gene and characterized telomerase-negative mutants. Similar to catalytic TERT mutants, ter1Δ mutants exhibit phenotypes of growth delay, telomere shortening and low replicative potential. ter1-disrupted mutants were unable to infect maize seedlings in heterozygous crosses and showed defects such as cell cycle arrest and segregation failure. We concluded that ter1, which encodes the TER subunit of the telomerase of U. maydis, have similar and perhaps more extensive functions than trt1.

Comparative genomics ofCryptococcusandKwoniellareveals pathogenesis evolution and contrasting karyotype dynamics via intercentromeric recombination or chromosome fusion

“…While similar defects in shelterin subunits or telomerase in Kwoniella could be promoting chromosome fusions, our analysis of did not reveal obvious defects in shelterin subunits or telomerase compared with Ustilago maydis [83, 137, 138], although the RNA subunit of telomerase in Kwoniella remains unidentified. While challenging to detect bioinformatically, innovative approaches like those used in U. maydis [139, 140] could be key. However, telomeric repeat sequences present at chromosome termini in Kwoniella suggests functional telomerase and intact telomeres.…”

Global Gene Expression of Post-Senescent Telomerase-Negative ter1Δ Strain of Ustilago maydis

“…The U. maydis 518 ( a2b2 ) strain was previously donated by WK. Holloman (Cornell Weill Medical Center, New York, NY, USA), the telomerase-negative derivative strains ter1-02 and ter1-24 ( a2b2 , ter1::hph ) were constructed and characterized as previously described in [ 25 ]. The parental strain was used as a control.…”

“…RNA extraction was performed as previously described [ 25 ]. For the elaboration and sequencing of cDNA libraries, the services of the Laboratorios de Servicios Genómicos (LabSerGen) de la Unidad de Genómica Avanzada, Laboratorios Nacionales de Genómica para la Biodiversidad (UGA-LANGEBIO) of the Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV) were used.…”

“…Multiple research groups have successfully addressed the efforts to elucidate the details of telomere metabolism in the basidiomycetous model organism U. maydis , which has reported the telomere structure and drafted its organization [ 21 , 22 , 23 , 24 ]. The two core subunits of the telomerase complex have been identified and partially characterized [ 22 , 25 ]; in addition, several hypothetical genes of the shelterin complex subunits have been identified, and some genes of the recombination machinery involved in chromosomal end maintenance have been characterized [ 23 , 24 , 26 ].…”

“…The TER subunit of the U. maydis telomerase is located on chr 8 as an overlapping sense lncRNA spanning the last exon of UMAG_03168 and the proximal intergenic sequence ter1 of 1626 bp (GenBank TPA: BK059259). The length of the gene has been calculated as at least 1280 bp; it transcribes more than one isoform, but the characterization of a full set of transcript products remains to be completed [ 25 ].…”