Carlos A H Fernandes1, Edna Gicela O Morea2, Gabriel A Dos Santos2, Vitor L da Silva2, Marina Roveri Vieira2, Maria Alejandra Viviescas2, Jean Chatain3, Aurélie Vadel3, Carole Saintomé4, Marcos Roberto M Fontes5, Maria Isabel Nogueira Cano6. 1. Department of Biophysics and Pharmacology, Biosciences Institute, São Paulo State University (UNESP) - Botucatu, SP, Brazil; Laboratoire de Biologie et Pharmacologie Appliquée, École Normale Supérieure Paris-Saclay, Cachan, France. 2. Department of Chemical and Biological Sciences, São Paulo State University (UNESP) - Botucatu, SP, Brazil. 3. MNHN CNRS UMR 7196, INSERM U1154, 43 rue Cuvier, 75005 Paris, France. 4. MNHN CNRS UMR 7196, INSERM U1154, 43 rue Cuvier, 75005 Paris, France; Sorbonne Université, UFR927, 4 place Jussieu, 75005 Paris, France. 5. Department of Biophysics and Pharmacology, Biosciences Institute, São Paulo State University (UNESP) - Botucatu, SP, Brazil. 6. Department of Chemical and Biological Sciences, São Paulo State University (UNESP) - Botucatu, SP, Brazil. Electronic address: maria.in.cano@unesp.br.
Abstract
BACKGROUND: Telomeres are chromosome end structures important in the maintenance of genome homeostasis. They are replenished by the action of telomerase and associated proteins, such as the OB (oligonucleotide/oligosaccharide-binding)-fold containing telomere-end binding proteins (TEBP) which plays an essential role in telomere maintenance and protection. The nature of TEBPs is well known in higher and some primitive eukaryotes, but it remains undetermined in trypanosomatids. Previous in silico searches have shown that there are no homologs of the classical TEPBs in trypanosomatids, including Leishmania sp. However, Replication Protein A subunit 1 (RPA-1), an OB-fold containing DNA-binding protein, was found co-localized with trypanosomatids telomeres and showed a high preference for the telomeric G-rich strand. METHODS AND RESULTS: We predicted the absence of structural homologs of OB-fold containing TEBPs in the Leishmania sp. genome using structural comparisons. We demonstrated by molecular docking that the ssDNA binding mode of LaRPA-1 shares features with the higher eukaryotes POT1 and RPA-1 crystal structures ssDNA binding mode. Using fluorescence spectroscopy, protein-DNA interaction assays, and FRET, we respectively show that LaRPA-1 shares some telomeric functions with the classical TEBPs since it can bind at least one telomeric repeat, protect the telomeric G-rich DNA from 3'-5' Exonuclease I digestion, and unfold telomeric G-quadruplex. CONCLUSIONS: Our results suggest that RPA-1 emerges as a TEBP in trypanosomatids, and in this context, we present two possible evolutionary landscapes of trypanosomatids RPA-1 that could reflect upon the evolution of OB-fold containing TEBPs from all eukaryotes.
BACKGROUND: Telomeres are chromosome end structures important in the maintenance of genome homeostasis. They are replenished by the action of telomerase and associated proteins, such as the OB (oligonucleotide/oligosaccharide-binding)-fold containing telomere-end binding proteins (TEBP) which plays an essential role in telomere maintenance and protection. The nature of TEBPs is well known in higher and some primitive eukaryotes, but it remains undetermined in trypanosomatids. Previous in silico searches have shown that there are no homologs of the classical TEPBs in trypanosomatids, including Leishmania sp. However, Replication Protein A subunit 1 (RPA-1), an OB-fold containing DNA-binding protein, was found co-localized with trypanosomatids telomeres and showed a high preference for the telomeric G-rich strand. METHODS AND RESULTS: We predicted the absence of structural homologs of OB-fold containing TEBPs in the Leishmania sp. genome using structural comparisons. We demonstrated by molecular docking that the ssDNA binding mode of LaRPA-1 shares features with the higher eukaryotes POT1 and RPA-1 crystal structures ssDNA binding mode. Using fluorescence spectroscopy, protein-DNA interaction assays, and FRET, we respectively show that LaRPA-1 shares some telomeric functions with the classical TEBPs since it can bind at least one telomeric repeat, protect the telomeric G-rich DNA from 3'-5' Exonuclease I digestion, and unfold telomeric G-quadruplex. CONCLUSIONS: Our results suggest that RPA-1 emerges as a TEBP in trypanosomatids, and in this context, we present two possible evolutionary landscapes of trypanosomatids RPA-1 that could reflect upon the evolution of OB-fold containing TEBPs from all eukaryotes.
Authors: Luiz H C Assis; Débora Andrade-Silva; Mark E Shiburah; Beatriz C D de Oliveira; Stephany C Paiva; Bryan E Abuchery; Yete G Ferri; Veronica S Fontes; Leilane S de Oliveira; Marcelo S da Silva; Maria Isabel N Cano Journal: Cells Date: 2021-11-16 Impact factor: 6.600
Authors: Beatriz C D de Oliveira; Mark E Shiburah; Stephany C Paiva; Marina R Vieira; Edna Gicela O Morea; Marcelo Santos da Silva; Cristiane de Santis Alves; Marcela Segatto; Fernanda Gutierrez-Rodrigues; Júlio C Borges; Rodrigo T Calado; Maria Isabel N Cano Journal: Front Cell Dev Biol Date: 2021-10-28