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Gene & Protein in Disease Enhancing fertility with CRISPR

assessment of the current uses and potential misuse of For instance, a study using CRISPR/Cas9 to generate
CRISPR technology to inform appropriate regulations in Tssk3 knockout mice identified TSSK3 as a crucial factor
reproductive technology. in spermiogenesis, suggesting its potential as a target for
the development of non-hormonal male contraceptives. 120
5. Potential for new applications of CRISPR
in reproductive biology 6. Improvements in efficiency and
specificity of CRISPR technology
CRISPR-based gene drives represent an emerging
technique with significant implications in reproductive To enhance the specificity and efficiency of CRISPR
biology. In particular, CRISPR gene drives are valuable for systems and address associated challenges, researchers
managing disease vectors and invasive species populations. have pursued various strategies. One approach involves the
For example, gene drives targeting female fertility modification of the Cas9 enzyme to enhance its selectivity,
reduction can effectively decrease mosquito populations while another strategy focuses on the development of new
that serve as vectors for diseases such as malaria. Advanced software for designing improved gRNA. Studies on the
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gene drives have been developed to minimize resistance optimization and engineering of highly specific single
while imposing a high reproductive load on laboratory- gRNA (sgRNA) have demonstrated different techniques.
contained mosquito populations. In addition, gene For instance, one study improved sgRNA specificity by
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drive technology is being explored as an alternative to optimizing its length, thereby reducing the risk of off-
rodenticides for controlling invasive rodent populations, target modifications. Efforts to enhance the efficiency
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offering potential benefits for agriculture, food security, and specificity of CRISPR technology also include the
conservation, and human health. 112,113 design of smaller nucleases. In an in vivo study conducted
Another avenue in CRISPR gene editing for reproductive on mouse liver, scientists synthesized small RNA-guided
biology involves epigenetic modifications. CRISPR nucleases (sRGN), demonstrating high specificity and
technology holds significant promise in contributing to efficiency in both mouse liver and human cell lines.
the field of epigenetic modifications, offering avenues These synthetic RGNs were further explored as a delivery
to alter genes, remodel germ lines, and manipulate sex mechanism advantageously packed in an all-in-one adeno-
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ratios. This precise gene editing technique, applicable associated virus vector. In addition, nanoparticle-based
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both in vitro and in vivo, possesses broad biological and delivery systems, such as lipid-based nanoparticles, have
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medical applications. Through the targeting of genes shown potential in increasing the specificity of CRISPR
involved in spermatogenesis and other reproductive technology, particularly in achieving high tissue-specific
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processes, CRISPR can facilitate the investigation of gene editing in mouse lung and liver tissues. To address
epigenetic alterations in reproductive biology, thereby off-target effects, modifications in off-target detection tests
enriching our understanding of gene function and disease aim to reduce accidental cleavage, potentially enhancing
treatment. Furthermore, CRISPR-mediated mutations the efficiency of CRISPR technology. 121,125 Another avenue
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can alter methylation patterns, providing insights into the involves the use of naturally occurring proteins, such as
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epigenetic control of gene expression. Overall, CRISPR anti-CRISPR proteins like AcrIF1, AcrIF2, and AcrIF4,
technology emerges as a powerful tool for studying the which can control and regulate CRISPR activities, confining
epigenetic changes during reproductive processes and gene editing to desired areas within the body. 84,126,127
for developing new therapeutic approaches to address Despite the formidable capabilities of CRISPR, a
reproductive health issues. significant research gap remains in accessing numerous
Furthermore, CRISPR/Cas genome editing has biological targets, primarily due to the absence of
revolutionized the field of reproductive biology, enabling efficient delivery systems following systemic injections.
the creation of knockout and knockin animals in novel Notably, three distinct biomolecular Cas9 and gRNA
ways that were previously challenging. The development formats, namely, plasmid DNA (pDNA), mRNA, and
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of efficient CRISPR tools for genome editing, coupled with Cas9 ribonucleoproteins, pose challenges in this context.
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rapid methods for their introduction into mammalian In a study by Shinmyo and Kawasaki, pX330 plasmids
cells and mouse zygotes, has yielded significant benefits expressing humanized Cas9 and sgRNAs were employed
for the study of reproductive biology. Another potential to target the Satb2 gene, inducing precise mutations in
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application in the near future is the development of the rodent brain through in utero electroporation. This
contraceptives using CRISPR technologies. CRISPR has approach not only allowed for precise gene manipulation
been utilized to study genes involved in crucial fertility but also provided insights into the functional consequences
processes in both male and female model organisms. within neural development, offering promise in exploring
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Volume 3 Issue 1 (2024) 9 https://doi.org/10.36922/gpd.2701