Suppression of genetic recombination in the pseudoautosomal region and at subtelomeres in mice with a hypomorphic Spo11 allele.

International audienceBACKGROUND: Homologous recombination is the key process that generates genetic diversity and drives evolution. SPO11 protein triggers recombination by introducing DNA double stranded breaks at discreet areas of the genome called recombination hotspots. The hotspot locations are largely determined by the DNA binding specificity of the PRDM9 protein in human, mice and most other mammals. In budding yeast Saccharomyces cerevisae, which lacks a Prdm9 gene, meiotic breaks are formed opportunistically in the regions of accessible chromatin, primarily at gene promoters. The genome-wide distribution of hotspots in this organism can be altered by tethering Spo11 protein to Gal4 recognition sequences in the strain expressing Spo11 attached to the DNA binding domain of the Gal4 transcription factor. To establish whether similar re-targeting of meiotic breaks can be achieved in PRDM9-containing organisms we have generated a Gal4BD-Spo11 mouse that expresses SPO11 protein joined to the DNA binding domain of yeast Gal4. RESULTS: We have mapped the genome-wide distribution of the recombination initiation sites in the Gal4BD-Spo11 mice. More than two hundred of the hotspots in these mice were novel and were likely defined by Gal4BD, as the Gal4 consensus motif was clustered around the centers in these hotspots. Surprisingly, meiotic DNA breaks in the Gal4BD-Spo11 mice were significantly depleted near the ends of chromosomes. The effect is particularly striking at the pseudoautosomal region of the X and Y chromosomes -- normally the hottest region in the genome. CONCLUSIONS: Our data suggest that specific, yet-unidentified factors influence the initiation of meiotic recombination at subtelomeric chromosomal regions

Endometrial Stromal Tumour: Clinicopathological Series of Seven Cases

Endometrial Stromal Tumour (EST) mimics other neoplasms and is difficult to diagnose due to its wide range of morphologies. This is a clinicopathological study of seven cases of EST, which includes Endometrial Stromal Nodule (ESN), Low-grade Endometrial Stromal Sarcoma (LGESS), and High-grade Endometrial Stromal Sarcoma (HGESS). The age ranges from 34 to 75 years. Five out of seven cases presented with abnormal uterine bleeding, abdominal pain, and were radiologically suspected to be leiomyomas. After histopathological and Immunohistochemical (IHC) examination, one was diagnosed as ESN, three as LGESS, and the remaining three cases as HGESS. One case was initially diagnosed as a cellular leiomyoma and experienced multiple recurrences, eventually being diagnosed as HGESS with a fatal outcome within 36 months of the onset of the first symptoms. ESN and LGESS should be differentiated from leiomyoma and leiomyosarcoma. IHC plays an important role in distinguishing these tumours from the more common smooth muscle counterparts

Rapid Screening for Entry Inhibitors of Highly Pathogenic Viruses under Low-Level Biocontainment

Emerging viruses including Nipah, Hendra, Lujo, and Junin viruses have enormous potential to spread rapidly. Nipah virus, after emerging as a zoonosis, has also evolved the capacity for human-to-human transmission. Most of the diseases caused by these pathogens are untreatable and require high biocontainment conditions. Universal methods for rapidly identifying and screening candidate antivirals are urgently needed. We have developed a modular antiviral platform strategy that relies on simple bioinformatic and genetic information about each pathogen. Central to this platform is the use of envelope glycoprotein cDNAs to establish multi-cycle replication systems under BSL2 conditions for viral pathogens that normally require BSL3 and BSL4 facilities. We generated monoclonal antibodies against Nipah G by cDNA immunization in rats, and we showed that these antibodies neutralize both Nipah and Hendra live viruses. We then used these effective Henipavirus inhibitors to validate our screening strategy. Our proposed strategy should contribute to the response capability for emerging infectious diseases, providing a way to initiate antiviral development immediately upon identifying novel viruses

Xanthogranulomatous pyelonephritis and renal tubulopapillary adenomas: A rare coexistence

Xanthogranulomatous pyelonephritis is an uncommon inflammatory condition accounting for 1% of chronic pyelonephritis cases. Clinically and radiologically it mimics other renal space occupying lesions. Hence, correct preoperative diagnosis is not possible in all cases and nephrectomy is done in most patients. Renal tubulopapillary adenomas are benign epithelial lesions of kidney found to be associated with papillary renal cell carcinoma, acquired renal cystic disease, long term hemodialysis, arteriosclerotic renal vascular disease, etc. Here, we report two cases of Xanthogranulomatous pyelonephritis associated with the rare finding of renal tubulopapillary adenomas

Macromolecular Structure Underlying Recognition in Innate Immunity

Immune molecules have evolved to distinguish “self “molecules from “non-self”, “altered self” and “danger” molecules. Recognition is mediated via interactions between pattern recognition receptor molecules (PPRs) and their ligands, which include hydrophobic and electrostatic interactions between amino acid residues on the PPRs and uncharged or charged groups on amino acid residues, sugar rings or DNA/RNA molecules. Recognition in innate immunity range from cases (C1q, mannin-binding protein etc) where recognition is orchestrated by interaction between many ligands with one receptor molecule, and density of interaction is necessary for strong specific recognition, distinct from weak non-specific binding, and cases such as TLRs and NLRs where recognition involves complexation of single receptor and ligand, followed by oligomerisation of the receptor molecule. The majority of PPR molecules bind and recognise a wide variety of ligands, e.g TLR4 recognises LPS (gram negative bacteria), Lipotechoic acid (gram positive bacteria), heat shock protein hsp60, respiratory syncytial virus fusion protein etc, molecules that are structurally dissimilar to each other. This indicates considerable flexibility in their binding domains (amino acid residue variations) and modes (hydrophobic and charged, direct or mediated via an adaptor molecule). However, in many cases there is a dearth of structural and molecular data available, required to delineate the mechanism of ligand binding underlining recognition in pathogen receptors in innate immunity. Insights into requirements of conformation, charge, surface etc in the recognition and function of innate immunity receptors and their activation pathways, based on current data can suggest valuable avenues for future work

Leydig cell tumor : A report of two cases with unusual presentation

Leydig cell tumors (LCTs) are rare testicular tumors. They constitute 1-3% of all testicular tumors. We report two cases of LCT, one benign and the other one malignant, representing both ends of the spectrum. The case of benign LCT presented with infertility and was found to have azoospermia, and subsequently underwent orchidectomy. Histopathologic examination revealed the presence of a benign LCT. Postoperative recovery was uneventful. The sperm count improved subsequently, and a year later, he fathered a child. The case of malignant LCT was seen in another 47 year old male who presented with cough. On examination, a testicular swelling was found, and after orchidectomy, he was diagnosed to have malignant LCT on histopathologic examination

Quest to develop a standard screening method for urothelial carcinoma using liquid-based cytology (The Paris System) and CK20

Background: Bladder cancer, the most common malignancy of the urinary tract is a leading cause of morbidity and mortality. But cystoscopy, which is till now the mainstay of screening, is an invasive, high-cost method with low sensitivity especially for flat lesions. Aim: To find a non-invasive and effective screening method with liquid-based cytology (LBC) using The Paris System (TPS) and CK20 immunocytochemistry. Materials and Methods: It was a prospective study including the patients with clinical or cystoscopic diagnosis of urinary bladder space occupying lesions (SOL). Both conventional (CC) and liquid-based cytology slides were prepared from urine samples. Slides were evaluated by two trained pathologists and categorized according to TPS guidelines. CK20 immunocytochemistry (ICC) was also performed. Consequent formalin-fixed paraffin embedded sections were blindly examined by another pathologist and was taken as gold standard for comparison. Statistical Analysis: All the statistical analysis were done using MedCalc version 15.8 [Mariakerke, Belgium: MedCalc Software 2015]. Results: The study included 150 cases with a mean age of 62.4 years. Five cases revealed unsatisfactory smears. Rest of the cases were categorized as the following: 18.1% as NH-GUC, 8% as LGUN, 22.1% as AUC, 15.4% as SH-GUC, 32.9% as HGUC. Kappa value of CC and LBC were strong (0.854). LBC alone showed very low specificity (58%) and PPV (74.8%) which improved on application of ICC (specificity: 97.4%, PPV: 96.3%). Conclusion: We conclude that CK20 ICC offers potential for accurate, non-invasive detection and surveillance of bladder cancer and is a better tool when combined with liquid-based cytology, reported using The Paris System