CCR5 gene knock-out mediated TALEN technique and its effects against HIV infection on lymphocytes and macrophages

Most strains of HIV-1 use CD4 and CCR5 as receptors for cell entry. A naturally occurring CCR5 gene mutation known as CCR5-Δ32 results in CCR5 dysfunction and makes the cells resistant to HIV-1 infection. Previously, two patients who received hematopoietic stem cell transplantation which carried homozygous CCR5-Δ32 have had their HIV-1 infection functionally cured, suggesting that gene-editing targeting CCR5 could make it possible for curing HIV-1 infection. Currently, the transcription activator-like effector nucleases (TALEN) system provides the highest accuracy on gene editing with good efficiency. In this study, I aim to establish a TALEN-based gene-editing platform targeting CCR5 for HIV-1 cure. Previous publication has indicated that mRNA has more advantages than DNA when delivered to the cells. Thus, firstly in this study, I optimized electroporation delivery of mRNAs to the cells and then the protocol of in vitro transcription of mRNA. After transfecting primary T cells with TALEN mRNAs, the expression of surface CCR5 was downregulated. The disruption of the CCR5 gene was confirmed on the genomic level. After HIV-1 challenge, the CCR5 gene-edited primary T cells showed increased HIV-1 resistance. Macrophages also express CD4 and CCR5, which makes them another target of HIV-1 besides CD4+ T cells. Moreover, HIV-1-infected macrophages are more resistant to immune attack and are a key reservoir of HIV-1. Thus, I tested this TALEN system on monocytes-derived-macrophages (MDMs). After transfection of the TALEN mRNAs, the surface CCR5 expression on the MDMs was also downregulated. The CCR5 gene knock-out was confirmed on the genomic level as well. The TALEN-treated MDMS showed increased resistance to HIV-1 infection compared with the un-edited controls after HIV-1 challenge. The result of this study provides evidence and support for using TALEN to knock out CCR5 as a method for curing HIV-1 infection.Open Acces

Vacuum induced transparency and photon number resolved Autler-Townes splitting in a three-level system

We study the absorption spectrum of a probe field by a {\Lambda}-type three-level system, which is coupled to a quantized control field through the two upper energy levels. The probe field is applied to the ground and the second excited states. When the quantized control field is in vacuum, we derive a threshold condition to discern vacuum induced transparency (VIT) and vacuum induced Autler- Townes splitting (ATS). We also find that the parameter change from VIT to vacuum induced ATS is very similar to that from broken PT symmetry to PT symmetry. Moreover, we find the photon number resolved spectrum in the parameter regime of vacuum induced ATS when the mean photon number of the quantized control field is changed from zero (vacuum) to a finite number. However, there is no photon number resolved spectrum in the parameter regime of VIT even that the quantized control field contains the finite number of photons. Finally, we further discuss possible experimental realization

Unsupervised Machine Translation On Dravidian Languages

Unsupervised neural machine translation (UNMT) is beneficial especially for low resource languages such as those from the Dravidian family. However, UNMT systems tend to fail in realistic scenarios involving actual low resource languages. Recent works propose to utilize auxiliary parallel data and have achieved state-of-the-art results. In this work, we focus on unsupervised translation between English and Kannada, a low resource Dravidian language. We additionally utilize a limited amount of auxiliary data between English and other related Dravidian languages. We show that unifying the writing systems is essential in unsupervised translation between the Dravidian languages. We explore several model architectures that use the auxiliary data in order to maximize knowledge sharing and enable UNMT for distant language pairs. Our experiments demonstrate that it is crucial to include auxiliary languages that are similar to our focal language, Kannada. Furthermore, we propose a metric to measure language similarity and show that it serves as a good indicator for selecting the auxiliary languages