Characterization of demethylating DNA glycosylase ROS1 from Nicotiana tabacum L.

One of the main mechanisms of epigenetic regulation in higher eukaryotes is based on the methylation of cytosine at the C5 position with the formation of 5-methylcytosine (mC), which is further recognized by regulatory proteins. In mammals, methylation mainly occurs in CG dinucleotides, while in plants it targets CG, CHG, and CHH sequences (H is any base but G). Correct maintenance of the DNA methylation status is based on the balance of methylation, passive demethylation, and active demethylation. While in mammals active demethylation is based on targeted regulated damage to mC in DNA followed by the action of repair enzymes, demethylation in plants is performed by specialized DNA glycosylases that hydrolyze the N-glycosidic bond of mC nucleotides. The genome of the model plant Arabidopsis thaliana encodes four paralogous proteins, two of which, DEMETER (DME) and REPRESSOR OF SILENCING 1 (ROS1), possess 5-methylcytosine-DNA glycosylase activity and are necessary for the regulation of development, response to infections and abiotic stress and silencing of transgenes and mobile elements. Homologues of DME and ROS1 are present in all plant groups; however, outside A. thaliana, they are poorly studied. Here we report the properties of a recombinant fragment of the ROS1 protein from Nicotiana tabacum (NtROS1), which contains all main structural domains required for catalytic activity. Using homologous modeling, we have constructed a structural model of NtROS1, which revealed folding characteristic of DNA glycosylases of the helix- hairpin-helix structural superfamily. The recombinant NtROS1 protein was able to remove mC bases from DNA, and the enzyme activity was barely affected by the methylation status of CG dinucleotides in the opposite strand. The enzyme removed 5-hydroxymethylcytosine (hmC) from DNA with a lower eff iciency, showing minimal activity in the presence of mC in the opposite strand. Expression of the NtROS1 gene in cultured human cells resulted in a global decrease in the level of genomic DNA methylation. In general, it can be said that the NtROS1 protein and other homologues of DME and ROS1 represent a promising scaffold for engineering enzymes to analyze the status of epigenetic methylation and to control gene activity.

Supportive care needs of patients following treatment for colorectal cancer: risk factors for unmet needs and the association between unmet needs and health-related quality of life-results from the ColoREctal Wellbeing (CREW) study.

PURPOSE: To investigate unmet needs of patients with colorectal cancer (CRC) at the end of treatment and whether unmet needs improve over time. Identify predictors of need following treatment and whether unmet need is associated with worse health-related quality of life (HRQoL). METHODS: As part of the UK ColoREctal Wellbeing (CREW) cohort study, patients treated for CRC completed the Supportive Care Needs Survey Short Form-34 (SCNS SF-34) 15 and 24 months following surgery, along with questionnaires measuring HRQoL, wellbeing, life events, social support, and confidence to manage their cancer before surgery, 3, 9, 15, and 24 months post-surgery. RESULTS: The SCNS SF-34 was completed by 526 patients at 15 months and 510 patients at 24 months. About one-quarter of patients had at least one moderate or severe unmet need at both time points. Psychological and physical unmet needs were the most common and did not improve over time. Over 60% of patients who reported 5 or more moderate or severe unmet needs at 15 months experienced the same level of unmet need at 24 months. HRQoL at the beginning of treatment predicted unmet needs at the end of treatment. Unmet needs, specifically physical, psychological, and health system and information needs, were associated with poorer health and HRQoL at the end of treatment. CONCLUSIONS: Unmet needs persist over time and are associated with HRQoL. Evaluation of HRQoL at the start of treatment would help inform the identification of vulnerable patients. Assessment and care planning in response to unmet needs should be integrated into person-centred care. IMPLICATIONS FOR CANCER SURVIVORS: Early identification of CRC patients at risk of unmet needs will help infrom personalised survivorship care plans. The implementation of personalised and tailored services are likely to confer HRQoL gains.

Main Strategies of Plant Expression System Glycoengineering for Producing Humanized Recombinant Pharmaceutical Proteins.

Most the pharmaceutical proteins are derived not from their natural sources, rather their recombinant analogs are synthesized in various expression systems. Plant expression systems, unlike mammalian cell cultures, combine simplicity and low cost of procaryotic systems and the ability for posttranslational modifications inherent in eucaryotes. More than 50% of all human proteins and more than 40% of the currently used pharmaceutical proteins are glycosylated, that is, they are glycoproteins, and their biological activity, pharmacodynamics, and immunogenicity depend on the correct glycosylation pattern. This review examines in detail the similarities and differences between N- and O-glycosylation in plant and mammalian cells, as well as the effect of plant glycans on the activity, pharmacokinetics, immunity, and intensity of biosynthesis of pharmaceutical proteins. The main current strategies of glycoengineering of plant expression systems aimed at obtaining fully humanized proteins for pharmaceutical application are summarized.

State of research in the field of the creation of plant vaccines for veterinary use.

Transgenic plants as an alternative of costly systems of recombinant immunogenic protein expression are the source for the production of cheap and highly efficient biotherapeuticals of new generation, including plant vaccines. In the present review, possibilities of plant system application for the production of recombinant proteins for veterinary use are considered, the history of the "edible vaccine" concept is briefly summarized, advantages and disadvantages of various plant systems for the expression of recombinant immunogenic proteins are discussed. The list of recombinant plant vaccines for veterinary use, which are at different stages of clinical trials, is presented.