ABSTRACT
The limited accessibility to ophthalmological services in remote regions of developing countries poses a significant challenge in visual healthcare. Cataracts and refractive errors are prominent causes of visual impairment, and surgery, despite being an efficient option, faces barriers in developing countries due to financial and geographical constraints. Humanitarian missions play a vital role in addressing this issue. The improvement in the accuracy of calculating IOL power through techniques such as keratometry and biometry is a fundamental step towards optimizing surgical outcomes and the quality of life for patients in these underserved regions. In this context, the consideration of keratometry and immersion ultrasound biometry as preoperative assessment standards in cataract surgeries in developing countries is presented as a pertinent and advisable strategy.
Subject(s)
Cataract Extraction , Medical Missions , Humans , Visual Acuity , Developing Countries , Altruism , Cataract/complications , Treatment Outcome , Health Services Accessibility , BiometryABSTRACT
The woodchuck hepatitis virus post-transcriptional regulatory element (WPRE) increases transgene expression from a variety of viral vectors, although the precise mechanism is not known. WPRE is most effective when placed downstream of the transgene, proximal to the polyadenylation signal. We hypothesized that WPRE likely reduces viral mRNA readthrough transcription by improving transcript termination, which in turn would increase viral titers and expression. Using a Cre-lox-mediated plasmid-based assay, we found significant readthrough transcription from gamma-retroviral vector (RV) long terminal repeat (wt RV-LTR) and RV LTR with a self-inactivating deletion (SIN RV-LTR). WPRE, when placed upstream of the RV LTRs, significantly reduced readthrough transcription. Readthrough, present at much lower levels with the SIN HIV-1 LV-LTR, was also reduced with WPRE. When placed in RV vectors, WPRE increased total RV genomic mRNA; and increased viral titers from transiently transfected 293T cells and stable PG13 producer cells by 7- to 15-fold. The mechanism of increased titers and expression was not due to increased nuclear mRNA export, increased rate of viral transcription or a significant increase in viral mRNA half-life. Our results showed that WPRE improved vector genomic transcript termination to increase titers and expression from RVs.
Subject(s)
Genetic Engineering , Genetic Vectors/genetics , Hepatitis B Virus, Woodchuck/genetics , Regulatory Elements, Transcriptional , Retroviridae/genetics , Transcription, Genetic , Animals , Cell Line , Gene Expression , Gene Expression Regulation, Viral , Genetic Vectors/metabolism , Humans , Leukemia Virus, Murine/genetics , RNA Processing, Post-Transcriptional , Reading Frames , Simian Immunodeficiency Virus/genetics , Terminal Repeat Sequences , Transfection , TransgenesABSTRACT
Williams-Beuren syndrome (WBS) is a developmental disorder associated with haploinsufficiency of multiple genes at 7q11.23. Here, we report the functional characterization of WBS critical region gene 14 (WBSCR14), a gene contained in the WBS commonly deleted region. It encodes a basic-helix--loop--helix leucine zipper (bHLHZip) transcription factor of the Myc/Max/Mad superfamily. WBSCR14 is expressed in multiple tissues, including regions of the brain and the intestinal tract. WBSCR14 forms heterodimers with the bHLHZip protein Mlx to bind the DNA sequence CACGTG. Like Max, Mlx has no intrinsic transcriptional activity, but its association with Mad1, Mad4, Mnt or WBSCR14 can repress E-box-dependent transcription. Preliminary results suggest a possible role of WBSCR14 in growth control. Our data support the view that the Max-like bHLHZip protein, Mlx, is a key element of a transcription factor network. We thus suggest that WBSCR14 may contribute to some aspects of the WBS pathology.
