Arg Variant Research Articles

TP53 Gene 72 Arg/Pro (rs1042522) single nucleotide polymorphism increases the risk and the severity of chronic lymphocytic leukemia.

Genetic variations in TP53 gene are known to be important in chronic lymphocytic leukemia (CLL) and may cause its inactivation which is associated with an aggressive form of the disease. Single nucleotide polymorphism (rs1042522:G>C) in TP53 gene at codon 72 encodes for arginine (Arg) or proline (Pro) variant which results in amino acid substitution affecting the apoptotic potential of TP53 protein. The aim of this study was to assess the correlation between TP53 codon 72 polymorphism and risk susceptibility as well as severity of CLL among Tunisian patients. A case-control study was conducted in Tunisia from February 2019 to November 2021, 160 de novo CLL patients and 160 healthy volunteers matched in age and gender were involved. DNA was extracted from peripheral blood mononuclear cells and the rs1042522 was analyzed using PCR-RFLP. Pro variant was associated with higher susceptibility to CLL than Arg variant (p= 0.023). A significant association was found between Pro variant and prognostic classification of Binet stage C (p= 0.001), low hemoglobin level (p= 0.003) and low platelet count (p= 0.016). We suggest that Pro variant may increase the risk of developing CLL in our population and could be associated with the severity of the disease.

KIF6 Trp719Arg Genetic Variant Increases Risk for Thoracic Aortic Dissection

KIF6 (kinesin family member 6), a protein coded by the KIF6 gene, serves an important intracellular function to transport organelles along microtubules. In a pilot study, we found that a common KIF6 Trp719Arg variant increased the propensity of thoracic aortic aneurysms (TAA) to suffer dissection (AD). The present study aims for a definite investigation of the predictive ability of KIF6 719Arg vis à vis AD. Confirmatory findings would enhance natural history prediction in TAA. 1108 subjects (899 aneurysm and 209 dissection patients) had KIF6 719Arg variant status determined. The 719Arg variant in the KIF6 gene correlated strongly with occurrence of AD. Specifically, KIF6 719Arg positivity (homozygous or heterozygous) was substantially more common in dissectors (69.8%) than non-dissectors (58.5%) (p = 0.003). Odds ratios (OR) for suffering aortic dissection ranged from 1.77 to 1.94 for Arg carriers in various dissection categories. These high OR associations were noted for both ascending and descending aneurysms and for homozygous and heterozygous Arg variant patients. The rate of aortic dissection over time was significantly higher for carriers of the Arg allele (p = 0.004). Additionally, Arg allele carriers were more likely to reach the combined endpoint of dissection or death (p = 0.03). We demonstrate the marked adverse impact of the 719Arg variant of the KIF6 gene on the likelihood that a TAA patient will suffer aortic dissection. Clinical assessment of the variant status of this molecularly important gene may provide a valuable "non-size" criterion to enhance surgical decision making above and beyond the currently used metric of aortic size (diameter).

Association between the Trp64Arg polymorphism of the ADRB3 gene and overactive bladder.

The β3 -adrenergic receptor (ADRB3) is very important in the regulation of the human detrusor muscle function. The well-known tryptophan64arginine polymorphism of the ADRB3 gene alters the response of the receptor to various stimuli, including adrenalin and noradrenalin, and may increase the susceptibility to develop overactive bladder (OAB). Therefore, this study was performed to determine whether ADRB3 Trp64Arg polymorphism is associated with the pathophysiology of OAB syndrome. The study group (n = 150) consists of 72 patients with OAB and 78 controls without OAB. Venous blood samples were taken from all participants to analyze the ADRB3 gene Trp64Arg polymorphism using polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) assay. We compared the distribution of Trp64Arg polymorphism and symptom severity in both OAB and non-OAB subjects using χ2 test and Mann-Whitney's U test, respectively. The frequency of the 64Arg variant (heterozygous plus homozygous) in OAB and non-OAB subjects was 15.3% and 14.1%, respectively. There was no statistically significant difference between the OAB and non-OAB groups in regard to the distribution frequency of ADRB3 Trp64Arg polymorphism. The total frequency (OAB + non-OAB, 76 women and 74 men) of the Arg64 variant allele was 5.9% and 10.8% in women and in men, respectively. Although the frequency of the Arg64 variant was nearly twofold higher in men compared to women, the difference was not statistically significant. These results demonstrated that the ADRB3 Trp64Arg polymorphism is not significantly associated with OAB syndrome in a sample of Turkish OAB patients.

Polymorphisms in MDM2 and TP53 Genes and Risk of Developing Therapy-Related Myeloid Neoplasms

One of the most severe complications after successful cancer therapy is the development of therapy-related myeloid neoplasms (t-MN). Constitutional genetic variation is likely to impact on t-MN risk. We aimed to evaluate if polymorphisms in the p53 pathway can be useful for predicting t-MN susceptibility. First, an association study revealed that the Pro variant of the TP53 Arg72Pro polymorphism and the G allele of the MDM2 SNP309 were associated with t-MN risk. The Arg variant of TP53 is more efficient at inducing apoptosis, whereas the Pro variant is a more potent inductor of cell cycle arrest and DNA repair. As regards MDM2 SNP309, the G allele is associated with attenuation of the p53 apoptotic response. Second, to evaluate the biological effect of the TP53 polymorphism, we established Jurkat isogenic cell lines expressing p53Arg or p53Pro. Jurkat p53Arg cells presented higher DNA damage and higher apoptotic potential than p53Pro cells, after treatment with chemotherapy agents. Only p53Pro cells presented t(15;17) translocation and del(5q). We suggest that failure to repair DNA lesions in p53Arg cells would lead them to apoptosis, whereas some p53Pro cells, prone to cell cycle arrest and DNA repair, could undergo misrepair, generating chromosomal abnormalities typical of t-MN.

Detection of Hpv Genotypes and Their Association With p53 Codon 72 Polymorphism in Prostate Cancer

Aim: In this study, we focused on the p53 codon 72 polymorphism and HPV infections as a possible contributing factor in susceptibility to prostate cancer (PCa). Methods: Eighty histopathologically confirmed prostate biopsies comprising of 40 cancer cases and 40 benign prostate hyperplasia cases were used. Results: A significant difference was not observed between HPV presence and PCa progression. Our results showed that the p53 protein with Arg (p53-Arg72) variant contributes to the development of PCa. Conclusion: There is a near-significant association between Arg/Arg polymorphism and PCa.

Association of P53 Codon 72 with Colon Cancer: the Role of Genetic Factors

AIM: Studies on the association between p53 codon 72 and colon cancer have given contrasting results: in some populations a positive association has been found with *Pro variant, in other with *Arg variant and in other populations no association has been observed .We have studied the possible effect of genetic variability within four common polymorphisms on the association between p53 codon 72 and colon cancer. METHODS AND MATERIAL: 106 subjects with colon cancer and 476 controls from the White population of Rome were studied. p53 codon 72, ACP1, PTPN22, ADA2 and ADA6 polymorphisms were determined by DNA analysis. Statistical analyses were carried out by SPSS programs. RESULTS: The proportions of the joint genotypes of *Pro allele carriers with *B/*B genotype of ACP1, with carriers of *T allele of PTPN22, with the ADA1*1/*1 genotype and with carriers of ADA6*1 allele are higher in colon cancer than in controls. A statistically significant positive correlation is observed in colon cancer between the proportion of *Pro allele carriers and the number of the four genetic factors considered. Sex and cancer grade influence this correlation. CONCLUSIONS: Common genetic polymorphisms influence the strength of correlation between p53 codon 72 and colon cancer suggesting a possible explanation of the contrasting result observed between different populations. Moreover, the results support the multi-factorial origin of cancer.

Association of p53Pro72Arg (rs1042522) and MDM2309 (rs2279744) polymorphisms with risk for cervical intraepthelial lesions and cervical cancer development in Macedonian women

High risk Human Papillomavirus (HPV) is an important etiological factor in initiation of squamous intraepithelial lesions (SIL), but not enough for malignant progression to cervical cancer (CCa). Single nucleotide polymorphisms (SNPs): rs1042522 within the codon 72 of p53 and rs2279744 within MDM2 promoter gene are plausible factors for development of SIL or CCa conferring increased attenuation of p53 pathway. We investigated the association of these SNPs with the HPV positive SIL and CCa among women from the Republic of Macedonia. Using a multiplex PCR SNaPShot analysis we genotyped rs1042522 and rs2279744 in 131 HPV positive women with SIL or CCa and 110 HPV and cytologicaly negative controls subject. No significant difference in either genotype or allelic frequencies for rs1042522 and rs2279744 between cases and control was found. The stratification of patients on the basis of the lesion grade revealed lower frequency of CC genotype and C allele of rs1042522 in HSIL and CCa compared to LSIL [GG vs CC; p=0.001, OR=0.4; CG vs CC; p=0.04, OR=0.03 and CG+ GG vs CC; p=0.004, OR=0.2]. Additionally TT genotype and T allele of MDM2 309 showed significantly lower frequency in HSIL and CCa group then in LSIL [G vs T p=0.02, OR=0.52; GG vs TT; p=0.04, OR=0.29; ТТ vs ТG+GG; p=0.007, OR=0.34].The Arg variant of rs1042522 and T allele/TT genotype of rs2279744 are associated with progression to LSIL to HSIL or CCa and may be used as prediction markers in CCa management, but the clinical relevant warrants further validation in large and well-designed studies

Pyranopterin Coordination Controls Molybdenum Electrochemistry in Escherichia coli Nitrate Reductase

We test the hypothesis that pyranopterin (PPT) coordination plays a critical role in defining molybdenum active site redox chemistry and reactivity in the mononuclear molybdoenzymes. The molybdenum atom of Escherichia coli nitrate reductase A (NarGHI) is coordinated by two PPT-dithiolene chelates that are defined as proximal and distal based on their proximity to a [4Fe-4S] cluster known as FS0. We examined variants of two sets of residues involved in PPT coordination: (i) those interacting directly or indirectly with the pyran oxygen of the bicyclic distal PPT (NarG-Ser(719), NarG-His(1163), and NarG-His(1184)); and (ii) those involved in bridging the two PPTs and stabilizing the oxidation state of the proximal PPT (NarG-His(1092) and NarG-His(1098)). A S719A variant has essentially no effect on the overall Mo(VI/IV) reduction potential, whereas the H1163A and H1184A variants elicit large effects (ΔEm values of -88 and -36 mV, respectively). Ala variants of His(1092) and His(1098) also elicit large ΔEm values of -143 and -101 mV, respectively. An Arg variant of His(1092) elicits a small ΔEm of +18 mV on the Mo(VI/IV) reduction potential. There is a linear correlation between the molybdenum Em value and both enzyme activity and the ability to support anaerobic respiratory growth on nitrate. These data support a non-innocent role for the PPT moieties in controlling active site metal redox chemistry and catalysis.

Molecular insights into the dynamics of pharmacogenetically important N-terminal variants of the human β2-adrenergic receptor.

The human β2-adrenergic receptor (β2AR), a member of the G-protein coupled receptor (GPCR) family, is expressed in bronchial smooth muscle cells. Upon activation by agonists, β2AR causes bronchodilation and relief in asthma patients. The N-terminal polymorphism of β2AR at the 16th position, Arg16Gly, has warranted a lot of attention since it is linked to variations in response to albuterol (agonist) treatment. Although the β2AR is one of the well-studied GPCRs, the N-terminus which harbors this mutation, is absent in all available experimental structures. The goal of this work was to study the molecular level differences between the N-terminal variants using structural modeling and atomistic molecular dynamics simulations. Our simulations reveal that the N-terminal region of the Arg variant shows greater dynamics than the Gly variant, leading to differential placement. Further, the position and dynamics of the N-terminal region, further, affects the ligand binding-site accessibility. Interestingly, long-range effects are also seen at the ligand binding site, which is marginally larger in the Gly as compared to the Arg variant resulting in the preferential docking of albuterol to the Gly variant. This study thus reveals key differences between the variants providing a molecular framework towards understanding the variable drug response in asthma patients.

TP53 single nucleotide polymorphism rs1042522 in salivary gland neoplasms

The TP53 single nucleotide polymorphism (SNP) rs1042522 encodes arginine (Arg) or proline (Pro). The Arg variant is more effective at inducing apoptosis than the Pro. We assessed this SNP through direct sequencing of benign and malignant salivary neoplasms of Brazilian patients and compared the results with healthy controls' data. BAX, BCL-2, and CASPASE-3 mRNA levels were assessed by quantitative polymerase chain reaction (qPCR) in a set of salivary tumors, and the results were correlated with the tumor genotype. We found a higher frequency of the Arg/Arg genotype in the malignant group. However, the SNP did not influence the age of onset in either benign or malignant tumors. The SNP was not associated with the transcription levels of apoptotic/antiapoptotic genes. Malignant salivary neoplasms showed a higher frequency of the allele encoding Arg and a higher frequency of the Arg/Arg genotype. However, the different genotypes did not impact the transcription of genes involved in apoptosis.

Codon 72 Polymorphism Of TP53 Gene Is a Novel Prognostic Marker For Thalidomide Therapy In Multiple Myeloma

Backgrounds and purposeRecently, newly developed drugs such as thalidomide, lenalidomide and bortezomib have significantly improved survival of the patients with multiple myeloma (MM). However, certain group of the patients who have characteristic high-risk cytogenetic changes such as deletion of TP53 tumor suppressor gene revealed significantly shorter survival. In patients with deletion of TP53 gene, the somatic point mutation in the residual TP53 gene has been reported to be rare. Thus, the exact role of alteration of TP53 gene in high-risk myeloma remains unclear. Polymorphism of TP53 gene at codon 72 in exon 4, CGC to CCC transition, leads to arginine (Arg) to proline (Pro) amino-acid substitution. Biological analyses showed that the Arg variant more efficiently induces expression of P21 and apoptosis via Ser-6 and 20 phosphorylation of p53 protein. In contrast the Pro variant is less resistant to MDM-2-mediated degradation and more potently induced cell-cycle arrest and DNA damage repair. Recently, clinical significance of this polymorphism has been extensively studied in solid tumors as well as hematological malignancies including non-Hodgkin lymphoma and leukemia. However, consistent association of the polymorphism with cancer risk has not been elucidated.The purpose of this study is to examine codon 72 polymorphism in patients with refractory multiple myeloma (MM) treated with thalidomide, and to elucidate its association with myeloma risk and outcome of thalidomide-therapy. Patients & methodsA total of 37 Japanese patients with refractory or relapsed MM who were treated with thalidomide monotherapy were included in this study. Three cases showed deletion of TP53 gene by fluorescence in situ hybridization (FISH) analyses. The codon 72 polymorphism was evaluated in the rest of 34 patients. Genomic DNA was isolated from bone marrow mononuclear cells. The genomic TP53 gene was amplified by polymerase chain reaction, and the amplified DNAs were directly sequenced. ResultsDirect DNA sequence showed that the Pro/Pro homozygote was observed in six patients (18%), Pro/Arg heterozygote in 12 (35%) and Arg/Arg homozygote in 16 (47%). There was no significant difference in the frequency of the polymorphism between the 34 Japanese MM patients and the healthy Japanese individuals (P=0.44). Thus, association of codon 72 polymorphism with myeloma risk has failed to be elucidated. The response rate to thalidomide therapy was 33% in the patients with Pro/Pro, 27% in Pro/Arg and 44% in Arg/Arg (P=0.49), respectively. Other clinical backgrounds including age, sex, Durie-Salomon stage, ISS stage, serum creatinine, albumin, b2M, calcium, hemoglobin levels and M-protein type were not correlated with TP53 codon 72 polymorphism, either.Progression free survival (PFS), overall survival (OS) and post-relapse survival were shown in Figure 1. The patients with Pro allele tended to show shorter PFS; 5 weeks for the patients with Pro/Pro versus 32 weeks for those with Pro/Arg plus Arg/Arg (P=0.07) (Figure 1). Overall survival (OS) of the patients with Pro/Pro, Pro/Arg and Arg/Arg allele was 18 weeks, 49 weeks and 133 weeks, respectively (P=0.027). Especially, the patients with Pro/Pro allele revealed significantly shorter OS compared with those with Pro/Arg plus Arg/Arg (18 weeks versus 100 weeks, P=0.023) (Figure 1). Significant difference of OS in patients with Pro/Pro+Pro/Arg vs Arg/Arg (P= 0.032) suggested the dominant effect of Pro allele for poorer prognosis. Post-relapse survival of the patients with Pro/Pro, Pro/Arg and Arg/Arg allele was 11, 42 and 64 weeks, respectively (P=0.054). Post-relapse survival for Pro/Pro versus Pro/Arg plus Arg/Arg were 11 weeks versus 64 weeks (P=0.029). ConclusionThese results indicated that codon 72 polymorphism did not correlated with myeloma risk, but significantly associated with therapeutic outcome. Namely, the patients with Pro allele revealed earlier relapse and shorter post-relapse survival, resulted in shorter OS in thalidomide therapy. Further evaluation is needed to clarify whether the codon 72 polymorphism will be a new prognostic marker for the treatment with novel drugs. [Display omitted] Disclosures:No relevant conflicts of interest to declare.

Brief Report: High‐Throughput Sequencing of IL23R Reveals a Low‐Frequency, Nonsynonymous Single‐Nucleotide Polymorphism That Is Associated With Ankylosing Spondylitis in a Han Chinese Population

Ankylosing spondylitis (AS) is a highly heritable common inflammatory arthritis that targets the spine and sacroiliac joints of the pelvis, causing pain and stiffness and leading eventually to joint fusion. Although previous studies have shown a strong association of IL23R with AS in white Europeans, similar studies in East Asian populations have shown no association with common variants of IL23R, suggesting either that IL23R variants have no role or that rare genetic variants contribute. The present study was undertaken to screen IL23R to identify rare variants associated with AS in Han Chinese. A 170-kb region containing IL23R and its flanking regions was sequenced in 50 patients with AS and 50 ethnically matched healthy control subjects from a Han Chinese population. In addition, the 30-kb region of peak association in white Europeans was sequenced in 650 patients with AS and 1,300 healthy controls. Validation genotyping was undertaken in 846 patients with AS and 1,308 healthy controls. We identified 1,047 variants, of which 729 were not found in the dbSNP genomic build 130. Several potentially functional rare variants in IL23R were identified, including one nonsynonomous single-nucleotide polymorphism (nsSNP), Gly(149) Arg (position 67421184 GA on chromosome 1). Validation genotyping showed that the Gly(149) Arg variant was associated with AS (odds ratio 0.61, P = 0.0054). This is the first study to implicate rare IL23R variants in the pathogenesis of AS. The results identified a low-frequency nsSNP with predicted loss-of-function effects that was protectively associated with AS in Han Chinese, suggesting that decreased function of the interleukin-23 (IL-23) receptor protects against AS. These findings further support the notion that IL-23 signaling has an important role in the pathogenesis of AS.

P53 Arg72Pro Polymorphism, HPV Status and Initiation, Progression, and Development of Cervical Cancer: A Systematic Review and Meta-Analysis

Cervical cancer develops through progression from normal cervical epithelium through squamous intraepithelial lesions (SIL) to invasive cancer. Cervical cancer is associated with oncogenic human papillomavirus (HPV). The HPV E6 oncoprotein binds to the tumor suppressor gene product p53, promoting its degradation; the Arg allele of p53 Arg72Pro polymorphism binds more ardently with HPV E6 than the Pro variant. Here we evaluate the role of p53 Arg72Pro polymorphism and HPV status on the initiation, progression, and development of cervical cancer. A systematic review and meta-analysis were conducted. Events of interest were the initiation of neoplasia (SIL vs. normal), progression to invasive cancer (cervical cancer vs. SIL), and risk of invasive cancer (cervical cancer vs. normal) by HPV status. OR were extracted from individual studies and pooled using generic inverse variance and random effects modeling. Forty-nine studies were included. In individuals showing HPV positivity, there was a significantly higher odds of progression from SIL to cervical cancer with the p53 Arg allele [OR 1.37; 95% confidence intervals (CI), 1.15-1.62; P < 0.001]. This association was not seen in HPV-negative individuals. p53 Arg72Pro was not associated with the risk of cervical cancer or initiation of SIL in either HPV-positive or HPV-negative patient subsets. The Arg variant of p53 Arg72Pro is associated with progression of SIL to cervical cancer only in the presence of HPV positivity. There were no associations of this variant with overall risk or initiation of cancer in either HPV-positive or HPV-negative patients. Clin Cancer Res; 18(23); 6407-15.

The Gly(972)Arg Variant of Human IRS1 Gene Is Associated With Variation in Glomerular Filtration Rate Likely Through Impaired Insulin Receptor Signaling

The objective of this study is to identify and characterize the genetic variants related to the glomerular filtration rate (GFR) linkage on 2q37. Of the positional candidate genes, we selected IRS1 and resequenced its 2-kb promoter region and exons for sequence variants in 32 subjects. A total of 11 single nucleotide polymorphisms (SNPs) were identified. To comprehensively cover the 59-kb-long intron-1, eight additional tagging SNPs were selected from the HapMap. All the 19 SNPs were genotyped by TaqMan Assay in the entire data set (N = 670; 39 families). Association analyses between the SNPs and GFR and type 2 diabetes–related traits were performed using the measured genotype approach. Of the SNPs examined for association, only the Gly(972)Arg variant of IRS1 exhibited a significant association with GFR (P = 0.0006) and serum triglycerides levels (P = 0.003), after accounting for trait-specific covariate effects. Carriers of Arg972 had significantly decreased GFR values. Gly(972)Arg contributed to 26% of the linkage signal on 2q. Expression of IRS1 mutant Arg972 in human mesangial cells significantly reduced the insulin-stimulated phosphorylation of IRS1 and Akt kinase. Taken together, the data provide the first evidence that genetic variation in IRS1 may influence variation in GFR probably through impaired insulin receptor signaling.

Association between autoantibodies to the Arginine variant of the Zinc transporter 8 (ZnT8) and stimulated C-peptide levels in Danish children and adolescents with newly diagnosed type 1 diabetes

The zinc transporter 8 (ZnT8) was recently identified as a common autoantigen in type 1 diabetes (T1D) and inclusion of ZnT8 autoantibodies (ZnT8Ab) was found to increase the diagnostic specificity of T1D. The main aims were to determine whether ZnT8Ab vary during follow-up 1 year after diagnosis, and to relate the reactivity of three types of ZnT8Ab to the residual stimulated C-peptide levels during the first year after diagnosis. A total of 129 newly diagnosed T1D patients <15 years was followed prospectively 1, 3, 6, and 12 months after diagnosis. Hemoglobin A1c, meal-stimulated C-peptide, ZnT8Ab, and other pancreatic autoantibodies were measured at each visit. Patients were genotyped for the rs13266634 variant at the SLC30A8 gene and HLA-DQ alleles. The levels of all ZnT8Ab [ZnT8Arg (arginine), ZnT8Trp (tryptophan), ZnT8Gln (glutamine)] tended to decrease during disease progression. A twofold higher level of ZnT8Arg and ZnT8Gln was associated with 4.6%/5.2% (p = 0.02), 5.3%/8.2% (p = 0.02) and 8.9%/9.7% (p = 0.004) higher concentrations of stimulated C-peptide 3, 6, and 12 months after diagnosis. The TT genotype carriers of the SLC30A8 gene had 45.8% (p = 0.01) and 60.1% (p = 0.002) lower stimulated C-peptide 6 and 12 months after diagnosis compared to the CC and the CT genotype carriers in a recessive model. The levels of the Arg variant of the ZnT8 autoantibodies are associated with higher levels of stimulated C-peptide after diagnosis of T1D and during follow-up. Carriers of the TT genotype of the SLC30A8 gene predict lower stimulated C-peptide levels 12 months after diagnosis.

Association of p53 Arg72Pro polymorphism and HPV status with the initiation, progression, and development of cervical cancer (CC): A meta-analysis.

1597 Background: CC develops through progression from normal cervical epithelium through squamous intra-epithelial lesions (SILs) to cancer. CC is classically associated with oncogenic human papillomavirus (HPV). Yet, not all CC patients demonstrate HPV infection at diagnosis. HPV+ and HPV– subsets of CC patients may thus represent distinct entities. HPV binds to P53, promoting its degradation; the Arg variant of p53 Arg72Pro binds more ardently to HPV than the Pro variant. Although there have been meta-analyses of Arg72Pro in CC risk, none has evaluated the relationship between Arg72Pro and HPV status together. We hypothesize that p53 Arg72Pro modifies aspects of the carcinogenic process in HPV+ (but not HPV-) subsets of CC. Methods: Pubmed/Embase databases identified 1494 potential studies; 51 were eligible and included. Separate analyses were performed to evaluate CC risk (CC vs normal), initiation of cancer (SIL vs normal), and progression towards cancer (CC vs SIL), by HPV status. Pooled odds ratios (pOR) were generated using RevMan 5.1 software. Results: p53 Arg72Pro was not associated with CC risk in either HPV+ or HPV- patient subsets (pORs 0.92; 95%CI, 0.6-1.3 and pORs 1.07; 95%CI, 0.7-1.7, respectively). Similarly, there was no association with the initiation of disease (SIL vs normal): pORs 0.96; 95%CI, 0.7-1.3 (HPV+ subset); 1.11; 95%CI, 0.9-1.4 (HPV- subset). There was no association with disease progression from SIL to CC in the HPV- subset (pOR, 0.98; 95%CI, 0.7-1.4). However, in the HPV+ subset, comparing the progression from SIL through to CC, there was strong and significant association: pOR, 1.37; 95%CI, 1.2-1.6 (p=4.0x10E-4), with no evidence of heterogeneity (I2 = 0%) or bias (by funnel plot). Sensitivity analyses demonstrated similarly significant results, even after taking into account differing quality of methodological designs and type of biological sample analyzed (tumour vs. blood) of the underlying studies. Associations were mainly restricted to Caucasian studies. Conclusions: In this meta-analysis, the Arg variant of p53 Arg72Pro was associated with progression of SIL to CC only in HPV+ subsets, but not to disease initiation or risk of CC.

Genetic variants of the insulin receptor substrate‐1 are influencing the therapeutic efficacy of oral antidiabetics

The therapeutic efficacy of oral hypoglycaemic drugs varies between individuals, and pharmacogenetic factors contribute to this variability. The Gly972Arg polymorphism in the insulin receptor substrate-1 (IRS-1) has been shown to play a role in insulin signal transduction and therapeutic failure to sulphonylurea drugs. We studied the association between the IRS-1 polymorphism and the haemoglobin A1c (HbA1c) level in diabetic patients treated with insulinotropic versus non-insulinotropic hypoglycaemic drugs as a marker for the efficacy of an antidiabetic treatment. Genotyping of the IRS-1 Arg(972) variant was performed in type 2 diabetes patients treated with either sulphonylurea drugs, glinides or insulin or with metformin, acarbose or glitazones using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Significantly higher HbA1c levels were observed in carriers of the Arg(972) variant after treatment with insulinotropic drugs compared to wild-type carriers (8.3 vs. 7.6%, p = 0.005, independent t-test). Furthermore, patients with secondary failure to insulinotropic hypoglycaemic drugs switching finally to insulin showed even higher HbA1c levels in carriers of Arg(972) compared to wild-type (8.7 vs. 7.6%, p = 0.005, independent t-test). Thus, we were able to replicate the earlier findings of an association between the IRS-1 Arg(972) variant and secondary failure to sulphonylurea drugs, and further observed a general association between HbA1c and this polymorphism in type 2 diabetes patients treated with insulinotropic hypoglycaemic drugs but not with metformin.

Basis for the Specificity and Activation of the Serpin Protein Z-dependent Proteinase Inhibitor (ZPI) as an Inhibitor of Membrane-associated Factor Xa

The serpin ZPI is a protein Z (PZ)-dependent specific inhibitor of membrane-associated factor Xa (fXa) despite having an unfavorable P1 Tyr. PZ accelerates the inhibition reaction approximately 2000-fold in the presence of phospholipid and Ca(2+). To elucidate the role of PZ, we determined the x-ray structure of Gla-domainless PZ (PZ(DeltaGD)) complexed with protein Z-dependent proteinase inhibitor (ZPI). The PZ pseudocatalytic domain bound ZPI at a novel site through ionic and polar interactions. Mutation of four ZPI contact residues eliminated PZ binding and membrane-dependent PZ acceleration of fXa inhibition. Modeling of the ternary Michaelis complex implicated ZPI residues Glu-313 and Glu-383 in fXa binding. Mutagenesis established that only Glu-313 is important, contributing approximately 5-10-fold to rate acceleration of fXa and fXIa inhibition. Limited conformational change in ZPI resulted from PZ binding, which contributed only approximately 2-fold to rate enhancement. Instead, template bridging from membrane association, together with previously demonstrated interaction of the fXa and ZPI Gla domains, resulted in an additional approximately 1000-fold rate enhancement. To understand why ZPI has P1 tyrosine, we examined a P1 Arg variant. This reacted at a diffusion-limited rate with fXa, even without PZ, and predominantly as substrate, reflecting both rapid acylation and deacylation. P1 tyrosine thus ensures that reaction with fXa or most other arginine-specific proteinases is insignificant unless PZ binds and localizes ZPI and fXa on the membrane, where the combined effects of Gla-Gla interaction, template bridging, and interaction of fXa with Glu-313 overcome the unfavorability of P1 Tyr and ensure a high rate of reaction as an inhibitor.

Association between TP53 gene ARG72PRO polymorphism and chromosome aberrations in human cancers

It is well known that the TP53 gene considerably influences on DNA repair processes. Polymorphisms in the TP53 gene, particularly the well-known Arg72Pro in codon 72 of exon 4 (Ex4+119 G>C; rs1042522), can modify the functionality of the p53 protein and activation of DNA repair. Actually, polymorphic variants Arg and Pro were found to have different properties of regulation of TP53-dependent DNA repair target genes, that can effect various levels of chromosome aberrations in cancer patients with these genotypes. Here, we studied frequency of chromatid breaks (CB), chromosome-type aberrations (CTA) and aberrant cells (AC) in cancer patients (n = 102) with various Arg72Pro genotypes. It was shown that the Arg variant of TP53 gene is associated with high frequency of AC and chromatid breaks. That is Arg/Arg carriers have more different chromosome aberrations in comparison to individuals with Arg/Pro and Pro/Pro genotypes (P < 0.05). Conversely, the lowest level of AC and chromatid breaks were detected in cancer patients with the Pro/Pro genotype. A completely unexpected result was that women with Arg/Arg genotype had the most high frequency of CB and AC in comparison to Arg/Pro and Pro/Pro women carriers (P < 0.001). In the group of male patients we did not show any differences in chromosome aberrations between carriers of Arg72Pro genotypes. In conclusion, the TP53 gene Arg72Pro polymorphism appreciably influence on occurrence of chromosome aberrations in cancer.

Variations at the Semiconserved Glycine in the IQ Domain Consensus Sequence Have a Major Impact on Ca2+-Dependent Switching in Calmodulin−IQ Domain Complexes

We have replaced the semiconserved Gly in the IQ domain consensus sequence with Ala, Arg, or Met in a reference sequence and determined how this affects its complexes with calmodulin. The K(d) for the Ca(2+)-free reference complex is 2.4 +/- 0.3 microM. The Ala and Arg replacements increase this to 5.4 +/- 0.4 and 6.2 +/- 0.5 microM, while the Met increases it to 26.4 +/- 2.5 microM. When Ca(2+) is bound to both calmodulin lobes, the K(d) for the reference complex is not significantly affected, but the K(d) for the Ala variant decreases to 0.9 +/- 0.04 microM, and the values for the Arg and Met variants decrease to 0.4 +/- 0.03 microM. Using mutant calmodulins, we defined the effect of Ca(2+) binding to each lobe, with the C-terminal preceding the N-terminal (C-->N) or vice versa (N-->C). In the C-->N order the first step increases the reference K(d) approximately 5-fold, while it decreases the values for the variants approximately 2- to approximately 10-fold. The second step decreases the K(d) values for the all of the complexes approximately 5-fold, suggesting that the N-terminal lobe does not interact with the semiconserved position after the first step. In the N-->C order the first step increases the K(d) values for the reference complex and Met and Ala variants approximately 15- to approximately 200-fold but does not affect the value for the Arg variant. The second step decreases the K(d) values for the reference and Arg variant approximately 10- and approximately 15-fold and the Ala and Met variants approximately 2000-fold. Thus, both steps in the N-->C order are sensitive to variations at the semiconserved position, while only the first is in the C-->N order. Due to energy coupling, this order is followed under equilibrium conditions.