Since 2015, severe hydropericardium-hepatitis syndrome (HHS), caused by a highly pathogenic fowl adenovirus 4 (FAdV-4), emerged in China. In our previous study, the FAdV-4 has been identified as a ...novel genotype with a unique 1966-bp nucleotide deletion (1966Del) between open reading frame 42 and 43. In this study, the natural 1966Del was frequently identified among 17 clinical isolates and other reported Chinese clinical strains. To investigate the relationship between 1966Del and the increased virulence of the novel FAdV-4, a CRISPR/Cas9 operating platform for FAdV-4 was developed for the first time in this study. Based on this platform, a Re1966 strain was rescued, inserted the relative 1966Del sequence of a nonpathogenic strain KR5. In the pathogenicity study, the Re1966 strain retained high virulence for specific-pathogen-free chickens, similar to the parental wild-type HLJFAd15, although the survival time of chickens infected with Re1966 was much longer. Therefore, the natural 1966Del was identified as a non-essential site for the increased virulence of the emerged novel FAdV-4. Although further research on the virulence-determining region or point within the genome of the novel FAdV-4 is needed, the CRISPR/Cas9 operating platform for the novel FAdV-4 was developed and successfully applied to edit the genomic DNA for the first time, and it provides a novel powerful tool for both basic virology studies and vaccine vector development of FAdVs.
KIAA0586, also known as Talpid3, plays critical roles in primary cilia formation and hedgehog signaling in humans. Variants in KIAA0586 could cause some different ciliopathies, including Joubert ...syndrome (JBTS), which is a clinically and genetically heterogeneous group of autosomal recessive neurological disorders.
A 9-month-old girl was diagnosed as JBTS by the "molar tooth sign" of the mid-brain and global developmental delay. By whole-exome sequencing, we identified a single nucleotide variant c.3303G > A and a 1.38-kb deletion in KIAA0586 in the proband. These two variants of KIAA0586 were consistent with the mode of autosomal recessive inheritance in the family, which was verified using Sanger sequencing.
This finding of a compound heterozygote with a 1.38-kb deletion and c.3303G > A gave a precise genetic diagnosis for the patient, and the novel 1.38-kb deletion also expanded the pathogenic variation spectrum of JBTS caused by KIAA0586.
Functional characterizations and molecular dissections of long noncoding RNAs (lncRNAs) are critical to understand their involvement in the cellular regulatory network. LncRNAs exert their effects ...through functional RNA domains that interact with other molecules, including proteins, DNA, and RNA. Here, we describe experimental procedures for generating genomic deletions in a human haploid cell line using the CRISPR/Cas9 system. This method can be applied to examine functions of lncRNAs and their domains by establishing knockout and partial deletion mutant cell lines. In addition, we describe a CRISPR-mediated knockin method for artificial tethering of partner RNA-binding proteins to lncRNAs and its use to validate lncRNA-mediated functions.
The prognostic value of phosphatase and tensin homolog (PTEN) loss in prostate cancer has primarily been evaluated by either fluorescence in situ hybridization (FISH) or immunohistochemistry (IHC). ...Previously, we found that PTEN loss by IHC was associated with increased risk of upgrading from biopsy (Gleason 3 + 3) to prostatectomy (Gleason 7+). Now, using an evaluable subset of 111 patients with adjacent biopsy sections, we analyzed the association between
PTEN
deletion in cancer and the odds of upgrading by a highly sensitive and specific four-color FISH assay. We also compared the concordance of PTEN loss by IHC and
PTEN
deletion by FISH.
PTEN
deletion was found in 27 % (12/45) of upgraded cases compared with 11 % (7/66) of controls (
P
= 0.03). Cancers with
PTEN
deletions were more likely to be upgraded than those without deletions (adjusting for age odds ratio = 3.40, 95 % confidence interval 1.14–10.11). With respect to concordance, of 93 biopsies with PTEN protein detected by IHC, 89 (96 %) had no
PTEN
deletion by FISH, and of 18 biopsies without PTEN protein by IHC, 15 had homozygous or hemizygous
PTEN
deletion by FISH. Only 4 biopsies of the 93 (4 %) with PTEN protein intact had
PTEN
deletion by FISH. When the regions of uncertainty in these biopsies were systematically studied by FISH, intra-tumoral variation of
PTEN
deletion was found, which could account for variation in immunoreactivity. Thus, FISH provides a different approach to determining PTEN loss when IHC is uncertain. Both FISH and IHC are concordant, showing consistent positive associations between PTEN loss and upgrading.
CRISPR/Cas9-based genome editing is an inexpensive and efficient tool for genetic modification. Here we present a methodological approach of establishing interleukin-17 receptor B (IL17RB) knockout ...cell lines using CRISPR/Cas9-mediated genomic deletion. IL17RB gene encodes for a cytokine receptor that specifically binds to IL17B and IL17E and overexpressed in various cancers. The method involves CRISPR design, CRISPR cloning, delivery of CRISPR clone into cells, and verification of IL17RB gene deletion by deletion screening primer design, genomic DNA extraction, and polymerase chain reaction (PCR). Similar approaches can be used for generating mammalian cell lines with gene knockout for other genes of interest.
Viruses are widely used as vectors for heterologous gene expression in cultured cells or natural hosts, and therefore a large number of viruses with exogenous sequences inserted into their genomes ...have been engineered. Many of these engineered viruses are viable and express heterologous proteins at high levels, but the inserted sequences often prove to be unstable over time and are rapidly lost, limiting heterologous protein expression. Although virologists are aware that inserted sequences can be unstable, processes leading to insert instability are rarely considered from an evolutionary perspective. Here, we review experimental work on the stability of inserted sequences over a broad range of viruses, and we present some theoretical considerations concerning insert stability. Different virus genome organizations strongly impact insert stability, and factors such as the position of insertion can have a strong effect. In addition, we argue that insert stability not only depends on the characteristics of a particular genome, but that it will also depend on the host environment and the demography of a virus population. The interplay between all factors affecting stability is complex, which makes it challenging to develop a general model to predict the stability of genomic insertions. We highlight key questions and future directions, finding that insert stability is a surprisingly complex problem and that there is need for mechanism-based, predictive models. Combining theoretical models with experimental tests for stability under varying conditions can lead to improved engineering of viral modified genomes, which is a valuable tool for understanding genome evolution as well as for biotechnological applications, such as gene therapy.
Several different genetic alterations in the etiology of Lynch syndrome (hereditary nonpolyposis colorectal cancer HNPCC) are known, mostly point mutations and genomic rearrangements in 1 of at least ...3 mismatch-repair (MMR) genes. However, no susceptibility factor has yet been identified in a significant part (30-50%) of clinicopathologically well-defined HNPCC families, suggesting the presence of other predisposing mechanisms. In a set of probands from 27 Lynch syndrome families who lacked evidence of a germline mutation in either the MSH2 or MLH1 gene, we performed genomic deletion screening with the use of multiplex ligation-dependent probe amplification (MLPA) and sequencing. We used immunohistochemistry (IHC) and microsatellite instability (MSI) analyses on samples of the probands of all families. Comparative analysis of mRNA transcripts was performed on blood leukocyte-derived samples from mutation carriers and noncarrier controls. We report that large germline deletions encompassing the last exons of the TACSTD1 gene, upstream of MSH2, cosegregate with the HNPCC phenotype in 19% (5/27) of families tested. The tumors of the carriers show high-level MSI and MSH2 protein loss. We show that these deletions, by removing the transcriptional termination sequences of the upstream gene, give rise to multiple TACSTD1/MSH2 fusion transcripts. Our results provide evidence that deletions removing the last exon of TACSTD1 constitute a distinct class of mutations predisposing to Lynch syndrome. Thus, analysis of the 3' region of the TACSTD1 gene should be included in the routine mutation screening protocols for HNPCC. Hum Mutat 30, 197-203, 2009.
Induced pluripotent stem cells (iPSCs) from patients are an attractive disease model to study tissues with poor accessibility such as the brain. Using this approach, we and others have shown that ...trisomy 21 results in genome-wide transcriptional dysregulations. The effects of loss of genes on chromosome 21 is much less characterized. Here, we use patient-derived neural cells from an individual with neurodevelopmental delay and a ring chromosome 21 with two deletions spanning 3.8 Mb at the terminal end of 21q22.3, containing 60 protein-coding genes. To investigate the molecular perturbations of the partial monosomy on neural cells, we established patient-derived iPSCs from fibroblasts retaining the ring chromosome 21, and we then induced iPSCs into neuroepithelial stem cells. RNA-Seq analysis of NESCs with the ring chromosome revealed downregulation of 18 genes within the deleted region together with global transcriptomic dysregulations when compared to euploid NESCs. Since the deletions on chromosome 21 represent a genetic "contrary" to trisomy of the corresponding region, we further compared the dysregulated transcriptomic profile in with that of two NESC lines with trisomy 21. The analysis revealed opposed expression changes for 23 genes on chromosome 21 as well as 149 non-chromosome 21 genes. Taken together, our results bring insights into the effects on the global and chromosome 21 specific gene expression from a partial monosomy of chromosome 21qter during early neuronal differentiation.
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