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Caracterization of long-noncoding telomeric RNAs in Leishmania major

Abstract

Protozoan from Leishmania genus belong to the Trypanosomatidae family and present peculiar biological characteristics that are not shared with other eukaryotes. Many Leishmania species are the causative agents of a spectrum of diseases known as leishmaniases which are transmit by insects. The disease presents different clinical manifestations and in Brazil several new cases occur each year, principally due to social economic conditions, malnutrition, migration, environmental and climate changes. There are no efficient vaccines or treatment protocols and the drugs actually used to treat the disease are highly cost and usually lead to toxicity and parasite resistance. Therefore, to improve the knowledge about Leishmania molecular biology and physiology is crucial for the development of new therapies and to find parasite-specific drug targets. Actually, telomeres have been considered potential molecular targets as they are responsible to maintain genome stability. Leishmania telomeres similarly to other eukaryotes, are nucleoprotein structures found at the end of the chromosomes composed by protein complexes associated with repetitive DNA (5'-TTAGGG-3'). Telomeres protect chromosome ends from fusion and degradation ensuring that the genetic information is correctly copied during the cell cycle progress. Telomerase is the enzyme responsible to maintain telomere length, which can be controlled by different mechanisms such as the action of long non-coding telomeric RNAs (LncRNA). Among the telomeric LncRNAs are the Telomerase RNA component (TER) which is crucial for telomerase activity because it contains the template sequence that is copied by telomerase during telomere elongation. TERRA, the Telomere Repeat containing RNA and its counterparts, are also involved with telomere length regulation, telomere damage response and alterations in the composition of telomeric chromatin. In Leishmania we have previously identified and partially characterized LeishTER (Leishmania telomerase RNA), and here we propose to verify if the knockdown and overexpression of LeishTER alter its interactions with telomerase RNP and/or disturb parasite telomere homeostasis. In relation to TERRA expression in Leishmania, although it was shown more than two decades ago that trypanosomatids telomeres are transcribed by different types of RNA polymerase, at that time it was not clearly defined the transcription initiation site and which telomeric strand was transcribed. Here we will test the existence of TERRA in Leishmania using independent RNA-Seq libraries and will try to identify putative TERRA transcripts using northern blot, RT-PCR and RNA-FISH. The functions of both LncRNA telomeric RNAs will be studied using both parasite life stages and during promatigotes cell cyle. (AU)

Scientific publications
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
FERNANDES, CARLOS A. H.; PEREZ, ARINA M.; BARROS, ANDREA C.; DREYER, THIAGO R.; DA SILVA, MARCELO S.; MOREA, EDNA GICELA O.; FONTES, MARCOS R. M.; CANO, MARIA ISABEL N. Dual cellular localization of the Leishmania amazonensis Rbp38 (LaRbp38) explains its affinity for telomeric and mitochondrial DNA. Biochimie, v. 162, p. 15-25, JUL 2019. Web of Science Citations: 0.
VIVIESCAS, MARIA ALEJANDRA; NOGUEIRA CANO, MARIA ISABEL; SEGATTO, MARCELA. Chaperones and Their Role in Telomerase Ribonucleoprotein Biogenesis and Telomere Maintenance. CURRENT PROTEOMICS, v. 16, n. 1, p. 31-43, 2019. Web of Science Citations: 0.
MOREA, EDNA G. O.; VIVIESCAS, MARIA ALEJANDRA; FERNANDES, CARLOS A. H.; MATIOLI, FABIO F.; LIRA, CRISTINA B. B.; FERNANDEZ, MARIBEL F.; MORAES, BARBARA S.; DA SILVA, MARCELO S.; STORTI, CAMILA B.; FONTES, MARCOS R. M.; CANO, MARIA ISABEL N. A calmodulin-like protein (LCALA) is a new Leishmania amazonensis candidate for telomere end-binding protein. BIOCHIMICA ET BIOPHYSICA ACTA-GENERAL SUBJECTS, v. 1861, n. 11, A, p. 2583-2597, NOV 2017. Web of Science Citations: 1.

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