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United States Department of Agriculture

Agricultural Research Service

Research Project: Integrated Strategies for Advanced Management of Fruit, Nut, and Oak Tree Diseases

Location: Crops Pathology and Genetics Research

Title: PRP8 intein in cryptic species of Histoplasma capsulatum: evolution and phylogeny

item Theodoro, Raquel
item Scheel, Christina
item Brandt, Mary
item Kasuga, Takao
item Bagagli, Eduardo

Submitted to: Infection, Genetics and Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/2/2013
Publication Date: 8/1/2013
Publication URL:
Citation: Theodoro, R.C., Scheel, C.M., Brandt, M.E., Kasuga, T., Bagagli, E. 2013. PRP8 intein in cryptic species of Histoplasma capsulatum: evolution and phylogeny. Infection, Genetics and Evolution. 18:174-182.

Interpretive Summary: The homing endonucleases are a type of restriction enzymes encoded by introns or inteins. They are considered to be selfish genetic elements, similar to transposons, because they facilitate the perpetuation of the genetic elements that encode them. These elements have been found in fungal and oomycete pathogens and are potential targets for anti-fungal drugs. Here we examined the distribution and relatedness of an intein coding sequence in the species complex of Histoplasma capsulatum, a widely distributed important pathogen of mammalians.

Technical Abstract: The PRP8 intein is the most widespread intein among the Kingdom Fungi. This genetic element occurs within the prp8 gene, and is transcribed and translated simultaneously with the gene. After translation, the intein excises itself from the Prp8 protein by an autocatalytic splicing reaction, subsequently joining the N and C terminals of the host protein, which retains its functional conformation. Besides the splicing domain, some PRP8 inteins also have a homing endonuclease (HE) domain which, if functional, makes the intein a mobile element capable of becoming fixed in a population. This work aimed to study 1) The occurrence of this intein in Histoplasma capsulatum isolates (n = 99) belonging to different cryptic species collected in diverse geographical locations, and 2) The functionality of the endonuclease domains of H. capsulatum PRP8 inteins and their phylogenetic relationship among the cryptic species. Our results suggest that the PRP8 intein is fixed in H. capsulatum populations and that eventual lateral transfer might have occurred among the clades from Latin America, probably by hybridization. The PRP8 intein sequences clearly separate the different cryptic species, and may serve as an additional molecular typing tool, as previously proposed for other fungi genus, such as Cryptococcus and Paracoccidioides.

Last Modified: 06/27/2017
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