The Protoparvovirus (PtPV) genus of the Parvoviridae family of viruses includes important animal pathogens and reference molecular models for the entire family. Some virus members of the PtPV genus have arisen as promising tools to treat tumoral processes, as they exhibit marked oncotropism and oncolytic activities while being nonpathogenic for humans. The PtPVs invade and replicate within the nucleus making extensive use of the transport, transcription and replication machineries of the host cells. In order to reach the nucleus, PtPVs need to cross over several intracellular barriers and traffic through different cell compartments, which limit their infection efficiency. In this review we summarize molecular interactions, capsid structural transitions and hijacking of cellular processes, by which the PtPVs enter and deliver their single-stranded DNA genome into the host cell nucleus. Understanding mechanisms that govern the complex PtPV entry will be instrumental in developing approaches to boost their anticancer therapeutic potential and improving their safety profile.
Hydroxyurea (HU), a drug which can reactivate fetal hemoglobin (Hb F) production, is frequently prescribed to β-thalassemia (β-thal) patients. However, transfusion requirements of only a subset of patients are reduced upon HU treatment. Because of its potential side-effects, targeted prescription of HU is imperative. To identify genetic markers that correlate with drug response, we have carried out a retrospective association study of single nucleotide polymorphisms (SNPs) in three Hb F quantitative trait loci (QTLs): the XmnI polymorphism, BCL11A, and the HBS1L-MYB intergenic region, with the response to HU in a cohort of 81 transfusion-dependent Iranian β-thal patients. An increase in blood transfusion intervals post-therapy was used to measure drug response. Our results suggest that presence of the XmnI T/T genotype or the BCL11A rs766432 C allele correlates strongly with response to HU (p <0.001). Accordingly, these markers may be used to accurately predict the HU response of Iranian β-thal patients.
A random 123 carriers of β-thalassemia (β-thal), identified by the Sulaimaniyah Provincial Premarital Screening Program in northeastern Iraq, were screened for β-thal mutations using multiplex polymerase chain reaction followed by reverse hybridization StripAssay and direct sequencing. A total of 11 different β-thal mutations was identified in the studied samples, of which eight represented 96% of the mutated β-globin genes. These were IVS-II-1 (G>A), IVS-I-110 (G>A), codon 8 (–AA), codons 8/9 (+G), IVS-I-5 (G>C), codon 5 (–CT), IVS-I-6 (T>C) and IVS-I-1 (G>A). Other mutations were less common or sporadic. There were some notable differences in frequencies of various mutations in comparison to other eastern Mediterranean populations, as well as with previous studies of Iraqi Kurds. The latter illustrate the relative heterogeneity of the mutations distributed in Iraq, and the need to screen other areas of the country, to ensure the establishment of an effective prenatal diagnosis program.
The 3.7 kb triplicated α-globin gene (ααα(anti 3.7)) mutation has been found in most populations. It results from an unequal crossover between misaligned homologous segments in the α-globin gene cluster during meiosis. The pathophysiology and clinical severity of β-thalassemia (β-thal) are associated with the degree of α chain imbalance. The excess of α-globin chains plays an important role in the pathophysiology of β-thal. When heterozygous/homozygous β-thal coexists with an α gene numerical alteration, the clinical and hematological phenotype of thalassemia could change to mild anemia in case of an α deletion (-α/αα) or severe anemia in the case of an α triplication (αα/ααα). The coexistence of an ααα(anti 3.7) triplication is considered an important factor in the severity of β-thal, exacerbating the phenotypic severity of β-thal by causing more globin chain imbalance. This study shows that the ααα(anti 3.7) triplication is an important factor in the causation of β-thal intermedia (β-TI) in heterozygous β-thal. This type of phenotype modification has rarely been observed and reported in the Iranian population. Here we report the coinheritance of a triplicated α-globin gene arrangement and heterozygous/homozygous β-thal in 23 cases, presenting with a β-TI or β-thal major (β-TM) phenotype. Some of these patients were considered to have a mild β-TI phenotype as they needed no blood transfusions; some occasionally received blood transfusions in their lifetime (for example on delivery) but some are dependent on regular blood transfusions (every 20 to 40 days). Our study was focused on the importance of detecting the α-globin gene triplication in genotype/phenotype prediction in Iranian thalassemia patients.
Thalassemia is the most common genetic disorder in Iran. Some α-globin genotypes leading to Hb H disease may cause severe anemia and dependence on regular blood transfusions. In this study, 40 patients were analyzed for the molecular basis and the genotype-phenotype correlation of Hb H disease in Iran. α-Globin molecular analysis was performed by polymerase chain reaction (PCR) followed by agarose gel electrophoresis, reverse hybridization test strips or DNA sequencing. The most frequently observed α-globin genotypes were -α(3.7)/- -(MED) in 10 patients (25%), - -(20.5)/α(-5nt)α in six patients (15%) and - -(20.5)/-α(3.7) in four patients (10%). A subset of the identified Hb H genotypes, including - -(MED)/α(CS)α, - -(MED)/α(PolyA2)α and α(CS)α/α(CS)α, was associated with a need for regular or irregular blood transfusions. Our findings provide a basis for predicting phenotype severity by identifying the Hb H genotype and making more selective decisions for prenatal diagnosis.
In an attempt to determine the spectrum of α-thalassemia (α-thal) mutations in the Kurdish population of Northeastern (NE) Iraq, a total of 101 unrelated adults with unexplained hypochromia and/or microcytosis were enrolled. α-Thalasssemia mutations were characterized by gap polymerase chain reaction (gap-PCR), multiplex PCR (m-PCR) and reverse hybridization and sequencing for both α genes. A total of nine α-thal mutations were characterized including four deletional ones: –α3.7 (rightward), – –MED-I, –(α)20.5, –α4.2 (leftward) and five nondeletional ones: αpolyA1α, ααAdana, α−5 ntα, αCSα and αpolyA2α. These determinants were arranged in 12 different genotypes, the most frequent of which were: –α3.7/αα, – –MED-I/αα, –α3.7/–α3.7, αpolyA1α/αα, ααAdana/αα and –(α)20.5/αα. This pattern is similar to that reported in Turkey, western (W) Iran, Cyprus and Greece, and to some extent, different from the pattern observed in the Arabian Peninsula.