Matrix Gene Of Influenza Research Articles

Molecular Characterization of Influenza A Viruses Detected in Children Attending Yangon Children’s Hospital, 2016

Sequence analysis of the influenza virus strains is important for molecular epidemiological studies and evolutional studies of influenza viruses as well as for the assessment of vaccine effectiveness. The aim of this study was to determine and characterize predominant subtype of influenza A viruses among children attending Yangon Children’s Hospital (YCH). It was a cross-sectional descriptive study conducted at YCH. Nasopharyngeal swabs were collected from 153 children who attended the hospital due to influenza-like illness (ILI) during January-December, 2016. Viral RNA was extracted by QIAamp® Viral Mini Kit. Matrix genes of influenza A and influenza B virus were detected by multiplex Reverse TranscriptionPolymerase Chain Reaction (RT-PCR). Influenza A virus matrix gene positive samples were subjected to subtyping. Predominant subtypes were subjected to sequencing and phylogenetic analysis of their HA gene and neuraminidase (NA) gene. Influenza viruses were detected in about 14% of children with ILI. Among them, 55% showed influenza A virus positive and 45% showed influenza B virus positive. Influenza A (H3N2) virus was found to be predominant among influenza A virus positive children accounting for 83.4%. There was one case (8.3%) of influenza A (H1N1) pdm09 virus and one case (8.3%) of unsubtyped influenza A virus. Phylogenetic analysis of HA and NA gene of two Myanmar strains of H3N2 subtype revealed that they belonged to clade 3C.2a1. They had 99.3-99.4% nucleotide identity with A/Hong Kong/ 4801/2014, vaccine strain of H3N2 subtype, that was contained in southern hemisphere influenza vaccine for 2016 and northern hemisphere vaccine for 2016-2017 season. This study generated information useful for the assessment of influenza outbreaks, selection of upcoming vaccine strains and further evolutionary and epidemiological studies on influenza viruses.

The matrix gene of influenza A H5N1 in Egypt, 2006-2016: molecular insights and distribution of amantadine-resistant variants.

Large-scale sequence analysis of Matrix (M) gene and its coding proteins M1 and M2 was performed for 274 highly pathogenic avian influenza viruses H5N1 circulated in Egypt from 2006 to 2016. The aim is to study the amantadine-resistant markers distribution and to estimate the evolutionary rate. 246 viruses were obtained from the Global Initiative on Sharing All Influenza Data base, and 28 additional viruses were sequenced. Maximum clade credibility (MCC) phylogenetic tree revealed that the M gene has evolved into two different lineages. Estimated Evolutionary analysis showed that the M2 protein possessed higher evolutionary rates (3.45×10-3) than the M1 protein (2.73×10-3). M gene encoding proteins revealed significant markers described to be associated with host tropism and increase in virulence: V15I, N30D, and T121A in M1 and L55F in M2 protein. Site analysis focusing attention on the temporal and host distribution of the amantadine-resistant markers was carried out and showed that vast majority of the M2 amantadine-resistant variants of clade 2.2.1.1 (n=90) is N31 marker, in addition to G27 (n=7), A27 (n=5), I27 (n=1), and S30 (n=1). In 2010-2011, amantadine resistant frequency increased considerably resembling more than half of the resistant variants. Notably, all viruses of clade 2.2.1.1 possessed amantadine-resistant marker. However, almost all current circulating viruses in Egypt of clade 2.2.1.2 from 2014 to 2016 did not carry any amantadine-resistant markers.

A real-time PCR assay for the monitoring of influenza a virus in wild birds

A screening system including a new real-time PCR assay for the monitoring of influenza A virus in wild birds was developed. The real-time PCR assay uses SYBR green chemistry and the primers are targeting the matrix gene of influenza A virus. The performance of the assay was compared with two other assays, one assay also using SYBR green chemistry and one assay using TaqMan chemistry, i.e. a specific probe. A total of 45 fecal bird samples were analysed for influenza A virus in three different PCR reactions. Overall, 26 samples were positive in at least one of the three real-time PCR assays. Of the 26 samples, 18 were positive by all three reactions. Eight samples were found positive exclusively by the two SYBR green reactions, six of which were detected by both SYBR green reactions. Of the 26 positive samples, 15 samples were verified as positive either by virus isolation or influenza A M2-gene PCR. The results showed that the two SYBR green systems had a higher performance regarding the detection of influenza A as compared to the PCR reaction using a specific probe.