The genus is an opportunistic fungal pathogen that infects patients with AIDS and immunocompromised individuals. The study of this fungus has been hampered due to the inability to grow it in a (defined media/pure) culture. However, the use of modern molecular techniques and genomic analysis has helped researchers to understand its complex cell biology. The transcriptional process in the genus has not been studied yet, although it is assumed that it has conventional transcriptional machinery. In this work, we have characterized the function of the RNA polymerase II (RNAPII) general transcription factor TFIIB from using the phylogenetically related biological model . The results of this work show that TFIIB i... More
The genus is an opportunistic fungal pathogen that infects patients with AIDS and immunocompromised individuals. The study of this fungus has been hampered due to the inability to grow it in a (defined media/pure) culture. However, the use of modern molecular techniques and genomic analysis has helped researchers to understand its complex cell biology. The transcriptional process in the genus has not been studied yet, although it is assumed that it has conventional transcriptional machinery. In this work, we have characterized the function of the RNA polymerase II (RNAPII) general transcription factor TFIIB from using the phylogenetically related biological model . The results of this work show that TFIIB is able to replace the essential function of TFIIB both in in vivo and in vitro assays. The strain harboring the TFIIB grew slower than the parental wild-type strain in complete media and in minimal media. The cells carrying out the TFIIB are larger than the wild-type cells, indicating that the TFIIB gene replacement confers a phenotype, most likely due to defects in transcription. TFIIB forms very weak complexes with TATA-binding protein on a TATA box promoter but it is able to form stable complexes in vitro when TFIIF/RNAPII are added. TFIIB can also replace the transcriptional function of TFIIB in an in vitro assay. The transcription start sites (TSS) of the endogenous gene do not change when TFIIB replaces TFIIB, and neither does the TSS of the gene, although this last gene is poorly transcribed in vivo in the presence of TFIIB. Since transcription by RNA polymerase II in is poorly understood, the results described in this study are promising and indicate that TFIIB from can replace the transcriptional functions of TFIIB, although the cells expressing the TFIIB show an altered phenotype. However, performing studies using a heterologous approach, like this one, could be relevant to understanding the basic molecular processes of such as transcription and replication.
