Focused Exome Sequencing Gives a High Diagnostic Yield in the Indian Subcontinent.

The genetically isolated yet heterogeneous and highly consanguineous Indian population has shown a higher prevalence of rare genetic disorders. However, there is a significant socioeconomic burden for genetic testing to be accessible to the general population. In the current study, we analyzed next-generation sequencing data generated through focused exome sequencing from individuals with different phenotypic manifestations referred for genetic testing to achieve a molecular diagnosis. Pathogenic or likely pathogenic variants are reported in 280 of 833 cases with a diagnostic yield of 33.6%. Homozygous sequence and copy number variants were found as positive diagnostic findings in 131 cases (15.7%) because of the high consanguinity in the Indian population. No relevant findings related to reported phenotype were identified in 6.2% of the cases. Patients referred for testing due to metabolic disorder and neuromuscular disorder had higher diagnostic yields. Carrier testing of asymptomatic individuals with a family history of the disease, through focused exome sequencing, achieved positive diagnosis in 54 of 118 cases tested. Copy number variants were also found in trans with single-nucleotide variants and mitochondrial variants in a few of the cases. The diagnostic yield and the findings from this study signify that a focused exome test is a good lower-cost alternative for whole-exome and whole-genome sequencing and as a first-tier approach to genetic testing.

A glutamate receptor C-tail recruits CaMKII to suppress retrograde homeostatic signaling.

Presynaptic homeostatic plasticity (PHP) adaptively enhances neurotransmitter release following diminished postsynaptic glutamate receptor (GluR) functionality to maintain synaptic strength. While much is known about PHP expression mechanisms, postsynaptic induction remains enigmatic. For over 20 years, diminished postsynaptic Ca2+ influx was hypothesized to reduce CaMKII activity and enable retrograde PHP signaling at the Drosophila neuromuscular junction. Here, we have interrogated inductive signaling and find that active CaMKII colocalizes with and requires the GluRIIA receptor subunit. Next, we generated Ca2+-impermeable GluRs to reveal that both CaMKII activity and PHP induction are Ca2+-insensitive. Rather, a GluRIIA C-tail domain is necessary and sufficient to recruit active CaMKII. Finally, chimeric receptors demonstrate that the GluRIIA tail constitutively occludes retrograde homeostatic signaling by stabilizing active CaMKII. Thus, the physical loss of the GluRIIA tail is sensed, rather than reduced Ca2+, to enable retrograde PHP signaling, highlighting a unique, Ca2+-independent control mechanism for CaMKII in gating homeostatic plasticity.

Metagenomic data of DNA viruses of poultry affected with respiratory tract infection.

The incidence and severity of respiratory diseases in commercial broiler chicken flocks have increased recently in India because of intensification of the broiler industry. Viral population are predominant in respiratory tract infections and they pose continuous economic burden to poultry industry by causing severe economic losses through decreased productivity [1], [2]. To understand viral metagenome of poultry associated with respiratory infections, we performed DNA virome sequencing and data analysis of broilers from 8 districts of Gujarat State in India. We report high quality sequencing reads and highly abundant DNA viral population present in the infected broiler birds. The raw sequencing data used to perform metagenomic analysis is available in the Sequence Read Archive (SRA) under the BioProject No. PRJNA322592 and Accession No. MAUZ00000000, MAVA00000000, MAVB00000000, MAVC00000000, MAVD00000000, MAVE00000000, MAVF00000000, MAVG00000000 (https://www.ncbi.nlm.nih.gov/bioproject/?term=PRJNA322592).

A transcriptomic insight into the infective juvenile stage of the insect parasitic nematode, Heterorhabditis indica.

BACKGROUND: Nematodes are the most numerous animals in the soil. Insect parasitic nematodes of the genus Heterorhabditis are capable of selectively seeking, infecting and killing their insect-hosts in the soil. The infective juvenile (IJ) stage of the Heterorhabditis nematodes is analogous to Caenorhabditis elegans dauer juvenile stage, which remains in 'arrested development' till it finds and infects a new insect-host in the soil. H. indica is the most prevalent species of Heterorhabditis in India. To understand the genes and molecular processes that govern the biology of the IJ stage, and to create a resource to facilitate functional genomics and genetic exploration, we sequenced the transcriptome of H. indica IJs. RESULTS: The de-novo sequence assembly using Velvet-Oases pipeline resulted in 13,593 unique transcripts at N50 of 1,371 bp, of which 53 % were annotated by blastx. H. indica transcripts showed higher orthology with parasitic nematodes as compared to free living nematodes. In-silico expression analysis showed 30 % of transcripts expressing with ≥100 FPKM value. All the four canonical dauer formation pathways like cGMP-PKG, insulin, dafachronic acid and TGF-ß were active in the IJ stage. Several other signaling pathways were highly represented in the transcriptome. Twenty-four orthologs of C. elegans RNAi pathway effector genes were discovered in H. indica, including nrde-3 that is reported for the first time in any of the parasitic nematodes. An ortholog of C. elegans tol-1 was also identified. Further, 272 kinases belonging to 137 groups, and several previously unidentified members of important gene classes were identified. CONCLUSIONS: We generated high-quality transcriptome sequence data from H. indica IJs for the first time. The transcripts showed high similarity with the parasitic nematodes, M. hapla, and A. suum as opposed to C. elegans, a species to which H. indica is more closely related. The high representation of transcripts from several signaling pathways in the IJs indicates that despite being a developmentally arrested stage; IJs are a hotbed of signaling and are actively interacting with their environment.

Identification of novel splice variants in horn cancer by RNA-Seq analysis in Zebu cattle.

Horn cancer accounts for nearly 83% of total tumors found in Indian Zebu cattle, which results in chronic suffering and causes heavy economic losses. Alternative splicing has been frequently implicated in the various types of cancer progression. Utilizing the transcriptome sequence generated by next generation sequencing, we analyzed the transcript data for the presence of alternative splicing using BLAT program and identified 27 alternatively spliced genes, of which 12 spliced variants appeared to be the novel spliced candidates. Protein prediction of these novel spliced variants revealed that splice variation has caused either truncation of protein, insertion/deletion of stretch of amino acids or formation of unique carboxy terminus. The RT-PCR analysis confirmed the expression of 8 of the 12 novel spliced variants observed by transcriptome sequencing. Additionally, altered splicing/expression of these novel candidates between cancer and normal tissues revealed by qPCR suggests their potential involvement in the development of horn cancer.

Identification of novel transcripts deregulated in buccal cancer by RNA-seq.

The differential transcriptome analysis provides better understanding of molecular pathways leading to cancer, which in turn allows designing the effective strategies for diagnosis, therapeutic intervention and prediction of therapeutic outcome. This study describes the transcriptome analysis of buccal cancer and normal tissue by CLC Genomics Workbench from the data generated by Roche's 454 sequencing platform, which identified total of 1797 and 2655 genes uniquely expressed in normal and cancer tissues, respectively with 2466 genes expressed in both tissues. Among the genes expressed in both tissues, 1842 were up-regulated whereas 624 were down-regulated in cancer tissue. Besides transcripts known to be involved in cancer, this study led to the identification of novel transcripts, with significantly altered expression in buccal cancer tissue, providing potential targets for diagnosis and cancer therapeutics. The functional categorization by the KEGG pathway and gene ontology analysis revealed enrichment of differentially expressed transcripts to various pathways leading to cancer, including the p53 signaling pathway. Moreover, the gene ontology analysis unfolded suppression of transcripts involved in actin mediated cell contraction process. The down-regulation of four of these transcripts MYL1, ACTA1, TCAP and DESMIN in buccal cancer were further supported by quantitative PCR signifying its possible implication in the cancer progression.

Metagenomic analysis of Surti buffalo (Bubalus bubalis) rumen: a preliminary study.

The complex microbiome of the rumen functions as an effective system for the conversion of plant cell wall biomass to microbial proteins, short chain fatty acids and gases. In this study, metagenomic approaches were used to study the microbial populations and metabolic potential of the microbial community. DNA was extracted from Surti Buffalo rumen samples (four treatments diet) and sequenced separately using a 454 GS FLX Titanium system. We used comparative metagenomics to examine metabolic potential and phylogenetic composition from pyrosequence data generated in four samples, considering phylogenetic composition and metabolic potentials in the rumen may remarkably be different with respect to nutrient utilization. Assignment of metagenomic sequences to SEED categories of the Metagenome Rapid Annotation using Subsystem Technology (MG-RAST) server revealed a genetic profile characteristic of fermentation of carbohydrates in a high roughage diet. The distribution of phylotypes and environmental gene tags (EGTs) detected within each rumen sample were dominated by Bacteroidetes/Chlorobi, Firmicutes and Proteobacteria in all the samples. The results of this study could help to determine the role of rumen microbes and their enzymes in plant polysaccharide breakdown is fundamental to understanding digestion and maximising productivity in ruminant animals.

A preliminary sketch of horn cancer transcriptome in Indian zebu cattle.

Horn cancer, a type of squamous cell carcinoma, in zebu cattle is an expensive affair in Indian agriculture sector, which accounts for 83.34% of total tumors found. In general, cancer tissue confirms considerably different expression patterns when compared to a normal stage. This includes not only up/down regulation, but also, the aberrant gene expression, the presence of different non-coding RNAs (ncRNAs), pseudogenes expression and genes involved in unusual pathways. We employed Roche 454 next generation sequencing platform to sequence Bos indicus cancerous and normal horn tissue transcripts. This resulted into a total of 909,345 high-confidence deep sequencing reads and detected a range of unusual transcriptional events including tumor associated genes. We also validated expression of two of the four tested genes in five other similar tissue samples by RT-qPCR. Further, seven cancer specific non-coding transcripts were accessed and a few of them have been suggested as cancer specific markers. This study for the first time provides primary transcriptome sketch of Bos indicus horn cancer tissue, and also demonstrates the suitability of the 454 sequencer for transcriptome analysis, which supports the concept of varied gene expression in cancerous condition.