New Mutations of the ID1 Gene in Acute Myeloid Leukemia Patients.

OBJECTIVES: Overexpression of the inhibitor of DNA binding 1 (ID1) protein is found in many types of cancer. In acute myeloid leukemia (AML), the expression of ID1 is induced by abnormal tyrosine kinases, such as FLT3 and BCR-ABL. High level expression of ID1 is associated with poor prognosis in young patients. We aimed to explore the ID1 mutation and its prognosis in AML patients. METHODS: Two hundred and sixty-three AML patients were included. Cytogenetic results and ID1 mutation were compared. The ID1 gene was amplified by nested PCR, and the mutation was identified by direct sequencing. RESULTS: Four new ID1 mutations (G40C, A124G, A230G, A349G) were identified in the normal karyotype patients. The A349G mutation, located in the nuclear export signal domain of the ID1 protein, was predicted by the in silico method as a damaged protein. Meanwhile, another new mutation, A290G, found in cases with 11q23 deletion, corresponded to the amino acid 97 in the helix 1 position of the ID1 protein. It could interfere with the dimerization of ID1 and EST-1, leading to a disruption of cell proliferation. CONCLUSIONS: In this study, we found 5 mutations in 260 AML patients. ID1 mutations were not commonly observed in AML. This may differ in other hematologic malignancies. Further studies in other types of hematologic malignancy will help to clarify the importance of ID1 mutations. © 2015 S. Karger AG, Basel.

Prevalence and gB genotype distribution of human cytomegalovirus among HIV sero-negative and HIV sero-positive orphans in Thailand.

BACKGROUND: Human Cytomegalovirus (HCMIV infects humans in all geographic areas. Polymorphisms ofglycoprotein B (gB) have been usedforgenotypic characterization of HCMV However information of gB genotyping of HCMV in Thailand is not clearly known especially in children. MATERIAL AND METHOD: A cross-sectional study was conducted to assess HCMV infection in 236 HIV seronegative and HIV seropositive children who attended an orphanage in Nonthaburi, Thailand by nested-PCR technique using urine specimens. HCMV gB genotypes were determined by restrictionfragment length polymorphism (RFLP), andDNA sequencing technique. RESULTS: Sixty-one percent (144/236) of the samples were HCMV positive, which consisted of 66.1% (37/56) of the HIV seropositive children and 59.4% (107/180) of the HIVsero-negative children. Multivariate analysis showed that children who living in one particular room were independently associated with HCMVinfection. Genotypic analysis revealed that the most prevalent genotype in these children was gB1; 85.4% (111/130) followed by gB3; 4.6% (6/130), gB2 and gB4 each at 2.3% (3/130). Mixed gB genotypes were identified in 5.4% (7/130) of the samples. CONCLUSION: HCMV infection, in particular gB1 genotype was commonly ident fled among these Thai orphans. Living in one particular room was associated with getting the infection. To prevent the transmission of HCMV infection in this setting, improvement in hygienic behavior ofchildcare workers should be focused.

Human cytomegalovirus gB1 genotypes among children who live at the Phayathai Babies' home in Nonthaburi, Thailand.

We conducted a survey of human cytomegalovirus (HCMV) genotypes among 176 children aged 1 month to 5 years living at Phayathai Babies' Home in Nonthaburi Province, Thailand to determine the prevalence of HCMV glycoprotein B (gB) genotype. The study was conducted on urine samples using nested polymerase chain reaction and restriction fragment length polymorphism; the HCMV gB1 genotype was found in 89% of subjects, much higher than previous reports. Our results show a high proportion of HCMV gB1 infected children in this population.

The Effect of a Single Nucleotide Substitution in the Splicing Silencer in the tat/rev Intron on HIV Type 1 Envelope Expression.

A complex mRNA splicing pattern, which remains to be fully characterized, influences HIV-1 gene expression. In this study, poor envelope expression of a primary HIV-1 isolate was observed and linked to increased splicing of the two coding exons of tat/rev. The substitution of a nucleotide G, located 28 nucleotides upstream of the splice acceptor site SA7 in the recently identified intron splicing silencer sequence, was found to be responsible for the poor envelope expression. A single nucleotide substitution of G with A at this position results in a poor envelope expression phenotype. Moreover, substitution of the nucleotide G with any other nucleotide in an infectious HIV-1 proviral clone, HXB2RU3, results in poor envelope expression. The substitution of this nucleotide reduces the hnRNP A1 binding affinity but increases the splicing of env mRNA. The nucleotide G at this position is highly conserved among HIV-1 isolates and appears to play a critical role in HIV-1 splicing.

Effect of amino acid substitution of the V3 and bridging sheet residues in human immunodeficiency virus type 1 subtype C gp120 on CCR5 utilization.

The V3 loop and the bridging sheet domain of human immunodeficiency virus type 1 (HIV-1) subtype B envelope glycoprotein gp120 have been implicated in CCR5 coreceptor utilization. In this study, mutant envelope glycoproteins of a subtype C isolate containing substitutions in the V3 or C4 region were generated to determine which are required for efficient CCR5-dependent cell fusion and viral entry. We found that the V3 crown and C4 residues are relatively dispensable for cell-cell fusion, although some residues may be involved in the regulation of early postentry steps in viral replication. In contrast, seven highly conserved residues located in the V3 stem are critical for CCR5 utilization, which can explain the apparent paradox that the functional convergence in CCR5 usage by genetically divergent HIV-1 strains involves a variable region. The finding that C4 residues do not have a critical role may appear to contradict the current model that bridging sheet residues are involved in the gp120-CCR5 interaction. However, a plausible interpretation is that these C4 residues may have a distinct role in the binding and fusion steps of the gp120-CCR5 interaction.