Referencia

Brissett NC, Martin MJ, Pitcher RS, Bianchi J, Juarez R, Green AJ, Fox GC, Blanco L, Doherty AJ. Mol Cell. 2011 Jan 21;41(2):221-31.

Autores

Nigel C. Brissett*, Maria Jose Martin*, Robert S. Pitcher, Julie Bianchi, Raquel Juarez, Andrew J. Green, Gavin C. Fox, Luis Blanco', and Aidan J. Doherty'. (* coauthors) ('co-corresponding authors)

Resumen

Grapando el ADN roto de la bacteria de la tuberculosis: Investigadores del Centro de Biología Molecular “Severo Ochoa” CBMSO (CSIC-UAM) llevan más de 10 años investigando sobre las proteínas implicadas en un importante mecanismo celular: el que repara las roturas de la doble hélice de ADN. En una investigación reciente, revelan nueva información sobre la manera como opera este mecanismo en la bacteria causante de la tuberculosis. La investigación, publicada en la revista Molecular Cell, ofrece una nueva visión sobre la reparación del ADN en bacterias y promete abrir puertas a nuevas formas de terapia contra estos agentes patógenos.

Descripción

In many prokaryotes, a specific DNA primase/polymerase (PolDom) is required for nonhomologous end joining (NHEJ) repair of DNA double-strand breaks (DSBs). Here,wereport the crystal structure of a catalytically active conformation of Mycobacterium tuberculosis PolDom, consisting of a polymerase bound to a DNA end with a 30 overhang, two metal ions, and an incoming nucleotide but, significantly, lacking a primer strand. This structure represents a polymerase:DNA complex in a preternary intermediate state. This polymerase complex occurs in solution, stabilizing the enzyme on DNA ends and promoting nucleotide extension of short incoming termini. We also demonstrate that the invariant Arg220, contained in a conserved loop (loop 2), plays an essential role in catalysis by regulating binding of a second metal ion in the active site. We propose that this NHEJ intermediate facilitates extension reactions involving critically short or noncomplementary DNA ends, thus promoting break repair and minimizing sequence loss during DSB repair.


Imágen artículo Abril

REFERENCIA DEL GRUPO E INVESTIGADOR
El laboratorio del Profesor Luis Blanco está especializado en el estudio de las únicas dos DNA polimerasas implicadas en la reparación de roturas de doble cadena (DSBs) en humanos, Pol lambda y Pol mu, identificadas en el laboratorio en 1999. Estas enzimas son relevantes para el mantenimiento del equilibro entre la estabilidad genómica y los niveles de variabilidad requeridos, no sólo para la evolución, sino para el normal funcionamiento de genes específicos. Una mala regulación de estos enzimas puede ser responsable de fenotipos mutadores asociados a carcinogénesis, como hemos demostrado recientemente para una variante polimórfica de Pol lambda, asociada a cáncer colorrectal. Datos recientes, en colaboración con M.A. Rodriguez Marcos (CBMSO, Madrid), indican que Pol mu, por su parte, es esencial para el desarrollo del sistema inmune del embrión. En colaboración con A. Doherty (Univ. Sussex, UK), hemos mostrado que algunas bacterias, tales como Mycobacterium tuberculosis, tienen un sistema muy eficiente de reparación de DSBs, basado en una ligasa multifuncional que contiene dominios con actividad nucleasa y polimerasa. Hemos encontrado interesantes paralelismos entre estos enzimas y Pol mu, siendo los primeros en resolver la estructura 3D del paso de sinapsis asociado a la reparación por reunión de extremos no homólogos (NHEJ) de una DSB.

Descárgate este artículo aquí.
Más artículos en la revista SEBBM.

Did you publish an interesting article recently?

Send it through our application form and we will contact you. Age limit: 32.

The selected articles will participate at the Award to the best article of young people of the SEBBM which will be given during SEBBM conference, that will take place at Spain (free registration, travel and accommodation).

More articles of the month

Macrophages promote endothelial-to-mesenchymal transition via MT1-MMP/TGFß after myocardial infarction

01-12-2020

Macrophages (Mφs) produce factors that participate in cardiac repair and remodeling after myocardial infarction (MI); however, how these factors crosstalk with other cell types mediating repair is not fully understood...

Read more

Cell identity and nucleo-mitochondrial genetic context modulate OXPHOS performance and determine somatic heteroplasmy dynamics

30-10-2020

Heteroplasmy, multiple variants of mitochondrial DNA (mtDNA) in the same cytoplasm, may be naturally generated by mutations but is counteracted by a genetic mtDNA bottleneck during oocyte development. Engineered heteroplasmic...

Read more

Mechanisms of autoregulation of C3G, activator of the GTPase Rap1, and its catalytic deregulation in lymphomas

01-10-2020

C3G is a guanine nucleotide exchange factor (GEF) that regulates cell adhesion and migration by activating the GTPase Rap1. The GEF activity of C3G is stimulated by the adaptor proteins...

Read more

Expression of the long non-coding RNA TCL6 is associated with clinical outcome in pediatric B-cell acute lymphoblastic leukemia

31-08-2020

The reciprocal translocation t(12;21)(p13;q22)[ETV6/RUNX1] is the most frequent chromosomal rearrangement in pediatric B-cell acute lymphoblastic leukemia(B-ALL). Long non-coding RNAs (lncRNAs) play important roles in numerous diseases and they represent an...

Read more

Evaluation of different approaches used to study membrane permeabilization by actinoporins on model lipid vesicles

30-07-2020

Release of aqueous contents from model lipid vesicles has been a standard procedure to evaluate pore formation efficiency by actinoporins, such as sticholysin II (StnII), for the last few decades...

Read more

ADAR1-mediated RNA editing is a novel oncogenic process in thyroid cancer and regulates miR-200 activity

01-07-2020

Adenosine deaminases acting on RNA (ADARs) convert adenosine to inosine in double-stranded RNA. A-to-I editing of RNA is a widespread posttranscriptional process that has recently emerged as an important mechanism...

Read more

Sarcoplasmic reticulum Ca2+ decreases with age and correlates with the decline in muscle function in Drosophila

29-05-2020

Sarcopenia, the loss of muscle mass and strength associated with age, has been linked to impairment of the cytosolic Ca2+ peak that triggers muscle contraction, but mechanistic details remain unknown...

Read more

Structural basis for substrate specificity and catalysis of α1,6-fucosyltransferase

30-04-2020

Core-fucosylation is an essential biological modification by which a fucose is transferred from GDP-β-L-fucose to the innermost N-acetylglucosamine residue of N-linked glycans. A single human enzyme α1,6-fucosyltransferase (FUT8) is the...

Read more

Molecular basis for fibroblast growth factor 23 O-glycosylation by GalNAc-T3

31-03-2020

Polypeptide GalNAc-transferase T3 (GalNAc-T3) regulates fibroblast growth factor 23 (FGF23) by O-glycosylating Thr178 in a furin proprotein processing motif RHT 178R ↓S. FGF23 regulates phosphate homeostasis and deficiency in GALNT3...

Read more

Identification of distinct maturation steps involved in human 40S ribosomal subunit biosynthesis

29-02-2020

Technical problems intrinsic to the purification of preribosome intermediates have limited our understanding of ribosome biosynthesis in humans. Addressing this issue is important given the implication of this biological process...

Read more

Protector Members