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Perlman Syndrome
Published in Dongyou Liu, Handbook of Tumor Syndromes, 2020
The DIS3L2 gene (a mammalian exosome-independent homolog of Schizosaccharomyces pombe yeast Dis3 gene) on chromosome 2q37.1 spans 383 kb and generates five splice variants, the longest of which encodes a 885 aa, 99.2 kDa protein (DIS3L2). Constituting a member of the highly conserved RNaseII/RNB family of 3′–5′ exoribonucleases, DIS3L2 demonstrates 3′/5′ exoribonucleolytic activity, which is critical for degradation of both mRNA and non-coding RNA. Specifically, 3′−5′ exoribonuclease recognizes mRNA and miRNA that are polyuridylated at the 3′ end by terminal uridylyltransferase and mediates their degradation. This RNA degradation pathway plays a vital role in the regulation of mitosis and cell proliferation [5,6].
Carbohydrates
Published in Geoffrey P. Webb, Nutrition, 2019
Lactose is a disaccharide found exclusively in milk and is the least sweet of the major dietary sugars. It is comprised of one unit of glucose and one of galactose. Lactose is the only significant source of galactose in the diet. Galactose is essential in several synthetic pathways but can be readily synthesised from glucose and so it is not an essential nutrient. On rare occasions, babies may inherit an enzyme deficiency that renders them unable to metabolise dietary galactose. In classic galactosaemia type 1, one of the enzymes that catalyses the four-step pathway from galactose to glucose (galactose-1-phosphate uridylyltransferase), is produced in an inactive form or has low activity depending upon the exact nature of the mutation. If such babies are fed with breast milk or lactose-containing infant formula, galactose accumulates in their blood (galactosaemia) and it is highly toxic. This high blood galactose results in a range of symptoms like vomiting after milk ingestion, failure to thrive and weight loss, liver enlargement and jaundice which may progress to cirrhosis of the liver. Cataracts and retarded mental development are also frequently found. Infants with this condition must be fed on a lactose-free formula and will need to continue to avoid milk and milk-containing foods after weaning. Even with apparently successful treatment, there may be some residual CNS effects such as delayed development of language skills.
Current progress of miRNA-derivative nucleotide drugs: modifications, delivery systems, applications
Published in Expert Opinion on Drug Delivery, 2022
Charles Asakiya, Liye Zhu, Jieyu Yuhan, Longjiao Zhu, Kunlun Huang, Wentao Xu
3’ modification could improve the stability of mdCNDs. In 2009, Katoh et al. designed a cytoplasmic poly (A) polymerase germline development 2 (GLD-2) (or terminal uridylyltransferase 2 (TUTase 2), which cause 3′ terminal adenylation, which protects miR-122 from degradation, thereby increasing its stability[30]. The results further revealed that a reduction in GLD-2 in liver cells led to the loss of the 23-nucleotide adenylated miR-122 variant but at the same time elongated the 21 nt variant. Therefore, this study indicates that GLD-2 loss of 3’ adenylation leaves miR-122 susceptible to exonuclease degradation. Many short RNAs (including miRNAs in plants and piRNAs in animals) require the Hua enhancer 1 (HEN1)-mediated 2′-O-methylation (2′-OMe) modification at the 3′ end for their stability[31]. Uridylation-mediated 3′-to-5′ truncation and 3′ tailing result in miRNA degradation and heterogeneity at the 3′ end.
Two consecutive pregnancies in a patient with premature ovarian insufficiency in the course of classic galactosemia and a review of the literature
Published in Gynecological Endocrinology, 2022
Jagoda Kruszewska, Hanna Laudy-Wiaderny, Sandra Krzywdzinska, Monika Grymowicz, Roman Smolarczyk, Blazej Meczekalski
Premature Ovarian Insufficiency (POI) is an impairment of the ovarian function before the age of 40, manifesting with menstrual abnormalities and infertility associated with decreased ovarian reserve [1]. Its diagnosis includes elevated concentration of FSH (>25 mIU/mL) observed twice at least 4 weeks apart and amenorrhea/oligomenorrhoea lasting for at least 4 months [2]. Among a wide spectrum of disorders leading to ovarian insufficiency is an autosomal recessive disease, known as classic galactosemia – an inborn defect of the enzyme GALT (galactose-1-phosphate uridylyltransferase) [3–5]. The risk of developing POI is high in individuals with galactosemia and its prevalence rate may even exceed 90% [6]. Importantly, ovarian dysfunction seems to be a diet-independent complication [7] and is observed, usually in adolescence, in the form of primary or secondary amenorrhea [8,9]. Generally, considering the other causes of POI, especially its idiopathic manifestation, the chance for spontaneous pregnancy is estimated to reach 5%–10% [10]. According to some authors, those rates in galactosemia may differ slightly [11,12]. In 2008, Gubbels et al. reviewed the literature and identified 50 galactosemic patients who successfully conceived [12]. We present a case report of a patient who became pregnant despite unfavorable factors.
Identification and characterization of a locus putatively involved in colanic acid biosynthesis in Vibrio alginolyticus ZJ-51
Published in Biofouling, 2018
Xiaochun Huang, Chang Chen, Chunhua Ren, Yingying Li, Yiqin Deng, Yiying Yang, Xiongqi Ding
Nucleotide sugars are the active form of sugars used as building blocks, so the production of nucleotide sugars is often the first step in polysaccharide synthesis. In EPSC, three pathways for nucleotide sugars were identified. The first contained the predicted genes, ORF19, ORF18, ORF16, ORF13, ORF15 and ORF14, coding mannose-6-phosphate isomerase (ManA), phosphomannomutase (ManB), mannose-1-phosphate guanyltransferase (ManC), GDP-mannose-4,6-dehydratase (Gmd), GDP-mannose mannosyl hydrolase (WcaH), and GDP-fucose synthetase (WcaG), respectively. They together catalyze the conversion of fructose-6-P to GDP-fucose. The second pathway participates in catalyzing Glc-1-P to UDP-glucose by ORF21-encoded GalU (UTP-glucose-1-phosphate uridylyltransferase). The third is to convert UDP-Glc to UDP-glucuronic acid by ORF20-encoded Ugd (UDP-glucose 6-dehydrogenase).