p53 signaling in cancer progression and therapy

The p53 protein is a transcription factor known as the "guardian of the genome" because of its critical function in preserving genomic integrity. The TP53 gene is mutated in approximately half of all human malignancies, including those of the breast, colon, lung, liver, prostate, bladder, and skin. When DNA damage occurs, the TP53 gene on human chromosome 17 stops the cell cycle. If p53 protein is mutated, the cell cycle is unrestricted and the damaged DNA is replicated, resulting in uncontrolled cell proliferation and cancer tumours. Tumor-associated p53 mutations are usually associated with phenotypes distinct from those caused by the loss of the tumor-suppressing function exerted by wild-type p53protein. Many of these mutant p53 proteins have oncogenic characteristics, and therefore modulate the ability of cancer cells to proliferate, escape apoptosis, invade and metastasize. Because p53 deficiency is so common in human cancer, this protein is an excellent option for cancer treatment. In this review, we will discuss some of the molecular pathways by which mutant p53 proteins might perform their oncogenic activities, as well as prospective treatment methods based on restoring tumor suppressive p53 functions.

Association study of RS535296987 in TEX14 gene in azoospermiamen: RFLP and DNA sequencing

Azoospermia is one of the kinds of male infertility, with clinically the most severe phenotype as the natural conception cannot occur. It has been estimated to affect 0.1 to 1% of all men and 10-15% of men in infertile couples. TEX14 (Testis expressed 14, intercellular bridge forming factor) is a protein coding gene, which is located in human chromosome 17, (17q22). Tex14 gene appears to be crucial for perfect spermatogenesis and functional studies indicate the role of TEX14 in the intercellular bridges between developing male germ cells. The gene contains 32 exons and spans 137 kb. A heterogeneousresultis available on the association TEX14 gene and azoospermia. Therefore, it is suggested to investigate this gene in different populations. We analyzed about 200 men in two categories of azoospermia and healthy persons by RFLP as well as DNA sequencing to indicate an association between rs535296987 in TEX14 and its adjacent nucleotides to azoospermia. We found no significant association based on RFLP data and also by clustering of case and control specimens based on DNA sequencing. In general, a low level of nucleotide variability was observed in DNA sequences. Therefore, both eternity in the studied samples and low degree of mutations in this genetic region, may be the reason for heterogeneous reports on association of TEX14 and azoospermia.

Targeted PMP22 TATA-box editing by CRISPR/Cas9 reduces demyelinating neuropathy of Charcot-Marie-Tooth disease type 1A in mice

Charcot-Marie-Tooth 1A (CMT1A) is the most common inherited neuropathy without a known therapy, which is caused by a 1.4 Mb duplication on human chromosome 17, which includes the gene encoding the peripheral myelin protein of 22 kDa (PMP22). Overexpressed PMP22 protein from its gene duplication is thought to cause demyelination and subsequently axonal degeneration in the peripheral nervous system (PNS). Here, we targeted TATA-box of human PMP22 promoter to normalize overexpressed PMP22 level in C22 mice, a mouse model of CMT1A harboring multiple copies of human PMP22. Direct local intraneural delivery of CRISPR/Cas9 designed to target TATA-box of PMP22 before the onset of disease, downregulates gene expression of PMP22 and preserves both myelin and axons. Notably, the same approach was effective in partial rescue of demyelination even after the onset of disease. Collectively, our data present a proof-of-concept that CRISPR/Cas9-mediated targeting of TATA-box can be utilized to treat CMT1A.

Gene Classification using Effective Random Forest Bootstrap Technique for Predicting the Gene Abnormalities

Gene classification is an increasing concern in the field of medicine for identifying various diseases at earlier stages. This work aims to specifically predict the abnormalities in human chromosome-17 by means of effective random forest bootstrap classification. The homo-sapiens dataset is initially preprocessed to remove the unwanted data. The enhanced data undergoes training phase where the appropriate and relevant features are selected by wrapper and filter methods. Based on the feature priorities, decision trees are formulated using random forest technique. The statistical quantities are estimated from the samples and a bootstrap sampling is designated. The effective bootstrap technique classifies the gene abnormalities in chromosome-17. The performance metrics are evaluated and the classification accuracy value is compared with the values of existing algorithms. From the experimental results, it is proved that the proposed method is highly accurate than the conventional methods.

Abstract 051: A Panel of CRISPR/Cas9 Genome Edited Rat Models Define Quantitative Trait Nucleotides within a Novel Rat Long Non-coding RNA Implicated in Cardiovascular Disease

This study is focused on a GWAS locus for cardiovascular disease (QT-interval) on human chromosome 17. The homologous genomic segment of this human locus was previously mapped with high resolution to <42.5 kb on rat chromosome 10. The locus in rats regulates both QT-interval and blood pressure and contains a novel long non-coding RNA (lncRNA), with a large 19bp deletion/insertion polymorphism observed between the strains used to map the locus. Characterization of this novel lncRNA using rapid amplification of cDNA ends (RACE) provided evidence for the presence of more than a single isoform of the lncRNA. To further assess the role of this locus, a panel of CRISPR/Cas9 based gene-edited ‘knockout’ models of the lncRNA was developed. The lncRNA targeted rats were developed on the genomic background of the hypertensive Dahl salt-sensitive rats and harbored varied disruptions around the critical 19bp region. The rat strains with the disrupted lncRNA sequences had a significantly elevated blood pressure compared with the controls. QT-interval is currently being examined. Overall, this is the first demonstration of a CRISPR/Cas9 based targeted gene-editing approach applied to identify a novel lncRNA as a Blood Pressure Quantitative Trait Locus.

The Angiotensin Converting Enzyme I/D Polymorphism in Turkish Athletes and Sedentary Controls

The angiotensin converting enzyme (ACE) gene is located on human chromosome 17 expressing three genotypes within the intron 16 of the related gene structure. These genotypes are classified as I and D alleles which are termed as insertion and deletion, respectively. This study was carried out to identify possible relationships between the insertion/ deletion (I/D) polymorphisms and athletic performance in Turkish athletes. To be able to determine these relationships, eighty healthy athletes and eighty healthy sedentary controls were genotyped for the ACE I/D polymorphism at gene level. According to the results obtained, we found significant difference on ACE I/D polymorphism in between athletes and healthy controls (x2 = 7.32, df = 2, P = 0.026). This result supports the association in ACE genotype in Turkish athletes, suggesting that this might be a genetic factor influencing the physical performance.