Focal segmental glomerulosclerosis (FSGS) is a histologically identifiable glomerular injury often leading to proteinuria and renal failure. To identify its causal genes, whole-exome sequencing and Sanger sequencing were performed on a large Chinese cohort that comprised 40 FSGS families, 50 sporadic FSGS patients, 9 independent autosomal recessive Alport's syndrome (ARAS) patients, and 190 ethnically matched healthy controls. Patients with extrarenal manifestations, indicating systemic diseases or other known hereditary renal diseases, were excluded. Heterozygous COL4A3 mutations were identified in five (12.5%) FSGS families and one (2%) sporadic FSGS patient. All identified mutations disrupted highly conserved protein sequences and none of them was found in either public databases or the 190 healthy controls. Of the FSGS patients with heterozygous COL4A3 mutations, segmental thinning of the glomerular base membrane (GBM) was only detected in the patient with electronic microscopy examination results available. Five ARAS patients (55.6%) had homozygous or compound-heterozygous mutations in COL4A3 or COL4A4. Serious changes in the GBM, hearing loss, and ocular abnormalities were found in 100%, 80%, and 40% of the ARAS patients, respectively. Overall, a new subgroup of FSGS patients resulting from heterozygous COL4A3 mutations was identified. The mutations are relatively frequent in families diagnosed with inherited forms of FSGS. Thus, we suggest screening for COL4A3 mutations in familial FSGS patients.

A single mammalian transcript normally encodes one protein, but the transcript of GNAS (G-protein α-subunit) contains two reading frames and produces two structurally unrelated proteins, XLαs and ALEX. No other confirmed GNAS-like dual-coding transcripts have been reported to date, even though many such candidate genes have been predicted by bioinformatics analysis. In this study, we constructed a series of vectors to test how two protein products were translated from a single transcript in vitro. The length of the ORF (open reading frame), position of the first AUG and the Kozak motif were found to be important factors. These factors, as well as 55-bp NMD (nonsense-mediated mRNA decay) rule, were used in a bioinformatics search for candidate dual-coding transcripts. A total of 1307, 750 and 474 two-ORF-containing transcripts were found in human, mouse and rat, respectively, of which 170, 89 and 70, respectively, were found to be potential dual-coding transcripts. Most transcripts showed low conservation among species. Interestingly, dual-coding transcripts were significantly enriched for transcripts from the zinc-finger protein family, which are usually DNA-binding proteins involved in regulation of the transcription process.

In addition to roles in stress response, heat shock factors (HSFs) play crucial roles in differentiation and development. Heat shock transcription factor 4 (HSF4) deficiency leads to defect in lens epithelial cell (LEC) differentiation and cataract formation. However, the mechanism remains obscure. Here, we identified Src kinase‐associated phosphoprotein 2 (SKAP2) as a downstream target of HSF4b and it was highly expressed at the anterior tip of lens elongating fibre cells in vivo. The HSF4‐deficient lenses showed reduced SKAP2 expression and defects in actin reorganization. The disassembly of stress fibres and formation of cortical actin fibres are critical for the initiation of LEC differentiation. SKAP2 localized at actin‐rich ruffles in human LECs (SRA01/04 cells) and knockdown SKAP2 using RNA interference impaired the disassembly of cellular stress fibres in response to fibroblast growth factor (FGF)‐b. Overexpression of SKAP2, but not the N‐terminal deletion mutant of SKAP2, induced the actin remodelling. We further found that SKAP2 interacted with the SH2 domain of non‐catalytic region of tyrosine kinase adaptor protein 2 (NCK2) via its N‐terminus. The complex of SKAP2‐NCK2‐F‐actin accumulated at the leading edge of the lamellipodium, where FGF receptors and focal adhesion were also recruited. These results revealed an essential role for HSF4‐mediated SKAP2 expression in the regulation of actin reorganization during lens differentiation, likely through a mechanism that SKAP2 anchors the complex of NCK2/focal adhesion to FGF receptors at the lamellipodium in lens epithelial cells.

Lung cancer is the most common cause of cancer mortality worldwide, with an estimated 1.4 million deaths each year. Here we report whole-exome sequencing of nine tumor/normal tissue pairs from Chinese patients with non-small cell lung carcinoma (NSCLC). This allows us to identify a number of significantly mutated genes in NSCLC, which were highly enriched in DNA damage repair, NF-κB pathway, JAK/STAT signaling and chromatin modification. Notably, we identify a histone-lysine methyltransferase gene, namely, MLL2, as one of the most significantly mutated genes in our screen. In a following validation study, we identify deleterious mutations of MLL2 in 12 out of 105 (11.4%) NSCLC patients. Additionally, reduced or lost expression of MLL2 was commonly observed in tumor tissues as compared with paired adjacent non-tumor tissues regardless of mutation status. Together, our study defines the landscape of somatic mutations in Chinese NSCLC and supports the role of MLL2 mutation in the pathogenesis of the disease.

Aberrant differentiation, driven by activation of normally silent tissue-specific genes, results in a switch of cell identity and often leads to cancer progression. The underlying genetic and epigenetic events are largely unexplored. Here, we report ectopic activation of the hepatobiliary-, intestinal- and neural-specific gene one cut homeobox 2 (ONECUT2) in various subtypes of lung cancer. ONECUT2 expression was associated with poor prognosis of RAS-driven lung adenocarcinoma. ONECUT2 overexpression promoted the malignant growth and invasion of A549 lung cancer cells in vitro, as well as xenograft tumorigenesis and bone metastases of these cells in vivo. Integrative transcriptomics and epigenomics analyses suggested that ONECUT2 promoted the trans-differentiation of lung cancer cells by preferentially targeting and regulating the activity of bivalent chromatin domains through modulating Polycomb Repressive Complex 2 (PRC2) occupancy. Our findings demonstrate that ONECUT2 is a lineage-specific and context-dependent oncogene in lung adenocarcinoma and suggest that ONECUT2 is a potential therapeutic target for these tumors.