"Tre recombinase" update

[leit]

Potential and obstacles:
http://www.jove.com/index/Details.stp?ID=793

[fortuneseeker]

Hope this come out ASAP in clinical test..
 

[bimazek]

wow that is great
esp. since he said in video there are already transgetic animals with tre recombinase and they dont have problems
meaning they can add that to humans and may not cause problems

watch all the segments esp. 3,4, 5 of video above
etc
also there is more here
http://www.jove.com/index/details.stp?ID=791
this video is amazing the german PhD guy says that they breed tre recombinase enzymes just like one would breed animals, you pick progeny that you want and then you make new versions of the enzyme just like pups
more evolution cycles -- evolving tre enzyme

[Matts]

It seems to work in humaniced mice so far:

"Highly Significant Antiviral Activity of HIV-1 LTR-Specific Tre-Recombinase in Humanized Mice

Abstract
Stable integration of HIV proviral DNA into host cell chromosomes, a hallmark and essential feature of the retroviral life cycle, establishes the infection permanently. Current antiretroviral combination drug therapy cannot cure HIV infection. However, expressing an engineered HIV-1 long terminal repeat (LTR) site-specific recombinase (Tre), shown to excise integrated proviral DNA in vitro, may provide a novel and highly promising antiviral strategy. We report here the conditional expression of Tre-recombinase from an advanced lentiviral self-inactivation (SIN) vector in HIV-infected cells. We demonstrate faithful transgene expression, resulting in accurate provirus excision in the absence of cytopathic effects. Moreover, pronounced Tre-mediated antiviral effects are demonstrated in vivo, particularly in humanized Rag2−/−γc−/− mice engrafted with either Tre-transduced primary CD4+ T cells, or Tre-transduced CD34+ hematopoietic stem and progenitor cells (HSC). Taken together, our data support the use of Tre-recombinase in novel therapy strategies aiming to provide a cure for HIV......

more:
http://www.plospathogens.org/article/info%3Adoi%2F10.1371%2Fjournal.ppat.1003587

http://tu-dresden.de/aktuelles/news/tre-rekombinase/newsarticle_view (german)

[Matts]

The reasearch is slow but ongoing. The Tre-recombinase was modified and is called "Universal Tre-recombinase" (uTre) now.

In the past Tre targeted only one specific HIV-Isolate, now it works against all HIV-1 isolates. At least in mice.

http://www.jiasociety.org/index.php/jias/article/view/19706/html

Universal Tre (uTre) recombinase specifically targets the majority of HIV-1 isolates

Abstract

Current drugs against HIV can suppress the progression to AIDS but cannot clear the patient from the virus. Because of potential side effects of these drugs and the possible development of drug resistance, finding a cure for HIV infection remains a high priority of HIV/AIDS research. We recently generated a recombinase (termed Tre) tailored to efficiently eradicate the provirus from the host genome of HIV-1 infected cells by specifically targeting a sequence that is present in the long terminal repeats (LTRs) of the viral DNA [1]. In vivo analyses in HIV-infected humanized mice demonstrated highly significant antiviral effects of Tre recombinase [2]. However, the fact that Tre recognizes a particular HIV-1 subtype A strain may limit its broad therapeutic application. To advance our Tre-based strategy towards a universally efficient cure, we have engineered a new, universal recombinase (uTre) applicable to the majority of HIV-1 infections by the various virus strains and subtypes. We employed the search tool SeLOX [3] in order to find a well-conserved HIV-1 proviral sequence that could serve as target site for a universal Tre from sequences compiled in the Los Alamos HIV Sequence Database. We selected a candidate (termed loxLTRu) with a mean conservation rate of 94% throughout the major HIV-1 subtype groups A, B and C. We applied loxLTRu as substrate in our established substrate-linked protein evolution (SLiPE) process [4] and evolved the uTre recombinase in 142 evolution cycles. Highly specific enzymatic activity on loxLTRu is demonstrated for uTre in both Escherichia coli and human cells. Naturally occurring viral variants with single mutations within the loxLTRu sequence are also shown to be efficiently targeted by uTre, further increasing the range of applicability of the recombinase. Potential off-target sites in the human genome are not recombined by uTre. Furthermore, uTre expression in primary human T cells shows no obvious Tre-related cytopathic or genotoxic effects. Finally, uTre expressing mice show no undesired phenotypes during their normal lifespan. We have developed a broad-range HIV-1 LTR specific recombinase that has the potential to be effective against the vast majority of HIV-1 strains and to cure HIV-1 infected cells from the infection. These results strongly encouraged us in our confidence that a Tre recombinase-mediated HIV eradication strategy may become a valuable component of a future therapy for HIV-infected patients.

Published 2 November 2014