Overexpression of DNA Polymerase Zeta Reduces the Mitochondrial Mutability Caused by Pathological Mutations in DNA Polymerase Gamma in Yeast

In yeast, DNA polymerase zeta (Rev3 and Rev7) and Rev1, involved in the error-prone translesion synthesis during replication of nuclear DNA, localize also in mitochondria. We show that overexpression of Rev3 reduced the mtDNA extended mutability caused by a subclass of pathological mutations in Mip1, the yeast mitochondrial DNA polymerase orthologous to human Pol gamma. This beneficial effect was synergistic with the effect achieved by increasing the dNTPs pools. Since overexpression of Rev3 is detrimental for nuclear DNA mutability, we constructed a mutant Rev3 isoform unable to migrate into the nucleus: its overexpression reduced mtDNA mutability without increasing the nuclear one

The EM structure of human DNA polymerase γ reveals a localized contact between the catalytic and accessory subunits

We used electron microscopy to examine the structure of human DNA pol γ, the heterotrimeric mtDNA replicase implicated in certain mitochondrial diseases and aging models. Separate analysis of negatively stained preparations of the catalytic subunit, pol γA, and of the holoenzyme including a dimeric accessory factor, pol γB2, permitted unambiguous identification of the position of the accessory factor within the holoenzyme. The model explains protection of a partial chymotryptic cleavage site after residue L549 of pol γA upon binding of the accessory subunit. This interaction region is near residue 467 of pol γA, where a disease-related mutation has been reported to impair binding of the B subunit. One pol γB subunit dominates contacts with the catalytic subunit, while the second B subunit is largely exposed to solvent. A model for pol γ is discussed that considers the effects of known mutations in the accessory subunit and the interaction of the enzyme with DNA

CAR T-cells for T-cell malignancies challenges in distinguishing between therapeutic, normal, and neoplastic T-cells

International audienceChimeric antigen receptor (CAR) T-cells targeting CD19 demonstrated remarkable efficacy for the treatment of B-cell malignancies. The development of CAR T-cells against T-cell malignancies appears more challenging due to the similarities between the therapeutic, normal and malignant T-cells. The obstacles include CAR T-cell fratricide, T-cell aplasia, and contamination of CAR T-cell products with malignant T-cells. Here, we review these challenges and propose solutions to overcome these limitations