Selenocysteine is incorporated cotranslationally at UGA codons, normally read as stop codons, in several bacterial proteins and in the mammalian proteins glutathione peroxidase (GPX), selenoprotein P and Type I iodothyronine 5' deiodinase (5'DI). Previous analyses in bacteria have suggested that a stem-loop structure involving the UGA codon and adjacent sequences is necessary and sufficient for selenocysteine incorporation into formate dehydrogenase and glycine reductase. We used the recently cloned 5'DI to investigate selenoprotein synthesis in eukaryotes. We show that successful incorporation of selenocysteine into this enzyme requires a specific 3' untranslated (3'ut) segment of about 200 nucleotides, which is found in both rat and human 5'DI messenger RNAs. These sequences are not required for expression of a cysteine-mutant deiodinase. Although there is little primary sequence similarity between the 3'ut regions of these mRNAs and those encoding GPX, the 3'ut sequences of rat GPX can substitute for the 5'DI sequences in directing selenocysteine insertion. Computer analyses predict similar stem-loop structures in the 3'ut regions of the 5'DI and GPX mRNAs. Limited mutations in these structures reduce or eliminate their capacity to permit 5'DI translation. These results identify a 'selenocysteine-insertion sequence' motif in the 3'ut region of these mRNAs that is essential for successful translation of 5'DI, presumably GPX, and possibly other eukaryotic selenocysteine-containing proteins.

Although thyroxine (3,5,3',5'-tetraiodothyronine, T4) is the principal secretory product of the vertebrate thyroid, its essential metabolic and developmental effects are all mediated by 3,5,3'-triiodothyronine (T3), which is produced from the prohormone by 5'-deiodination. The type-I iodothyronine deiodinase, a thiol-requiring propylthiouracil-sensitive oxidoreductase, is found mainly in liver and kidney and provides most of the circulating T3(1) but so far this enzyme has not been purified. Using expression cloning in the Xenopus oocyte, we have isolated a 2.1-kilobase complementary DNA for this deiodinase from a rat liver cDNA library. The kinetic properties of the protein expressed in transient assay systems, the tissue distribution of the messenger RNA, and its changes with thyroid status, all confirm its identity. We find that the mRNA for this enzyme contains a UGA codon for selenocysteine which is necessary for maximal enzyme activity. This explains why conversion of T4 to T3 is impaired in experimental selenium deficiency and identifies an essential role for this trace element in thyroid hormone action.

We investigated the requirements for selenocysteine insertion at single or multiple UGA codons in eukaryotic selenoproteins. Two functional SECIS elements were identified in the 3′ untranslated region of the rat selenoprotein P mRNA, with predicted stem‐loops and critical nucleotides similar to those in the SECIS elements in the type I iodothyronine 5′ deiodinase (5′DI) and glutathione peroxidase selenoprotein mRNAs. Site‐directed mutational analyses of three SECIS elements confirmed that conserved nucleotides in the loop and in unpaired regions of the stem are critical for activity. This indicates that multiple contact sites are required for SECIS function. Stop codon function at any of five out‐of‐context UGA codons in the 5′DI mRNA was suppressed by SECIS elements from the 5′DI or selenoprotein P genes linked downstream. Thus, the presence of SECIS elements in eukaryotic selenoprotein mRNAs permits complete flexibility in UGA codon position.

Bacteria and archaea possess adaptive immunity against foreign genetic materials through clustered regularly interspaced short palindromic repeat (CRISPR) systems. The discovery of this intriguing bacterial system heralded a revolutionary change in the field of medical science. The CRISPR and CRISPR-associated protein 9 (Cas9) based molecular mechanism has been applied to genome editing. This CRISPR-Cas9 technique is now able to mediate precise genetic corrections or disruptions in in vitro and in vivo environments. The accuracy and versatility of CRISPR-Cas have been capitalized upon in biological and medical research and bring new hope to cancer research. Cancer involves complex alterations and multiple mutations, translocations and chromosomal losses and gains. The ability to identify and correct such mutations is an important goal in cancer treatment. In the context of this complex cancer genomic landscape, there is a need for a simple and flexible genetic tool that can easily identify functional cancer driver genes within a comparatively short time. The CRISPR-Cas system shows promising potential for modeling, repairing and correcting genetic events in different types of cancer. This article reviews the concept of CRISPR-Cas, its application and related advantages in oncology.

A prevalent and distinctive infectious interstitial pneumonia (IIP) of immunocompetent laboratory rats was suspected to be caused by a putative virus, termed rat respiratory virus, but this was never substantiated. To study this disease, 2 isolators were independently populated with rats from colonies with endemic disease, which was perpetuated by the regular addition of naive rats. After Pneumocystis was demonstrated by histopathology and polymerase chain reaction (PCR) in the lungs of rats from both isolators and an earlier bedding transmission study, the relationship between Pneumocystis and IIP was explored further by analyzing specimens from 3 contact transmission experiments, diagnostic submissions, and barrier room breeding colonies, including 1 with and 49 without IIP. Quantitative (q) PCR and immunofluorescence assay only detected Pneumocystis infection and serum antibodies in rats from experiments or colonies in which IIP was diagnosed by histopathology. In immunocompetent hosts, the Pneumocystis concentration in lungs corresponded to the severity and prevalence of IIP; seroconversion occurred when IIP developed and was followed by the concurrent clearance of Pneumocystis from lungs and resolution of disease. Experimentally infected immunodeficient RNU rats, by contrast, did not seroconvert to Pneumocystis or recover from infection. qPCR found Pneumocystis at significantly higher concentrations and much more often in lungs than in bronchial and nasal washes and failed to detect Pneumocystis in oral swabs. The sequences of a mitochondrial ribosomal large-subunit gene region for Pneumocystis from 11 distinct IIP sources were all identical to that of P. carinii. These data provide substantial evidence that P. carinii causes IIP in immunocompetent rats.

The analysis of facial soft tissue from the photographic records gives information about the standard normative values of different facial parameters of a specific population group, helps in the diagnosis of any abnormalities of face and also helps for the treatment plan of patients undergoing orthodontic treatment or facial plastic surgery. The aim of the present study was to measure some craniofacial angles of the Bangladeshi Garo males and females on standardized facial profile photographs and compare them with each other and with norms of different ethnic group proposed by the other investigators. The study was carried out with a total number of 100 Christian Garo adult male and female subjects. Statistical analysis showed that the females had significantly higher values than the males in three facial angles (p < 0.05): the nasofrontal angle (G-N-Pro, females = 137.97˚ ± 4.80˚; males = 129.57˚ ± 7.96˚), the nasomental angle (N-Prn-Pg, females = 132.79˚ ± 5.10˚; males = 129.75˚ ± 7.32˚) and the angle of facial convexity (G-Sn-Pg, females = 169.26˚ ± 4.43˚; males = 158.65˚ ± 12.17˚) but no differences between the nasofacial (G-Pg/ N-Prn) and nasolabial angle (Cm-Sn-Ls). Findings from the present study might help to establish a distinct facial profile trait for the Garo population.

This study examined whether circulating levels of soluble receptor for advanced glycation end products (sRAGE) alter in prediabetes and correlate with insulin resistance (IR) and beta cell function in prediabetes and newly diagnosed type 2 diabetes mellitus (T2DM). Subjects without previous history of diabetes were recruited and grouped as control, prediabetes, and newly diagnosed T2DM. The control subjects (n = 40) and people with prediabetes (n = 52) and diabetes (n = 66) were similar in terms of age, sex, BMI, systolic and diastolic BP, and fasting insulin level. HOMA-IR was found significantly higher in people with diabetes than control subjects (p < 0.001) and people with prediabetes (p = 0.005); and HOMA-%B was found significantly deteriorated in people with diabetes (p < 0.001) compared to control subjects and people with prediabetes. However, serum sRAGE levels did not show any significant alteration in people with prediabetes compared to control subjects. Moreover, univariate and multivariate analyses did not identify any significant correlation and statistical association of sRAGE with HOMA-IR and HOMA-%B in people with prediabetes and newly diagnosed T2DM. Our data suggest that serum sRAGE levels do not alter in people with prediabetes compared to control subjects and do not correlate or associate with IR and beta cell function during development of T2DM.

Background: Worldwide, breast cancer is the leading cause of cancer death in female, in Bangladesh breast cancer is the second leading cancer in both sexes, and in women it occupied the top position. Highly penetrant mutations in BRCA1 gene constitute high risk of breast cancer. The spectrum of BRCA1 gene mutations varies in different population. The objective of this study was to identify mutation in exon11 of BRCA1 gene in Bangladeshi breast cancer patients. Methods: Genomic DNA was extracted from the histopathologically diagnosed formalin fixed paraffin embedded (FFPE) breast cancer tissues of 65 adult female patients. Two regions of exon11 of the BRCA1 gene were amplified and the amplicons were sequenced using Sanger sequencing. The sequenced nucleotides were analyzed and blast using NCBI nucleoblast. Selected demographic, reproductive and medical histories were collected and analyzed using SPSS version 20. Results: The mean age of the patients was 46 years and the mean age at diagnosis was 44.64 years. The patients were married and had 2.65 ± 1.22 children except one was nulliparous, the mean age of menarche was 12.67 years. All patients had children, breastfed the babies for an average 1.5 years. Only 13.6% of the patients had hypertension and the rest had no comorbidity. The family history for cancer (breast and other cancer) was negative. Three novel mutations were found in a patient. Two among the three mutant sequences had effect on amino acid coding (DNA sequence change g.852G>C and g.709G>A and amino acid changes p.Gln284His and p.Glu237Lys respectively). Conclusion: We found three novel mutations in Bangladeshi breast cancer patients. This finding indicates the necessity to study the mutation profile of whole BRCA1 gene in our population for cancer risk prediction.