China
Africa
Explore chapters and articles related to this topic
The Genetic Alibi
Published in Roy J. Shephard, Obesity: A Kinesiologist’s Perspective, 2018
Some of the genes at the relevant loci produce substances that are highly expressed in the central nervous system, particularly in the arcuate nucleus of the hypothalamus. These regions of the brain are known to influence appetite, satiety, energy expenditures, and behavioural patterns [46]. Thus, the fat mass and obesity-associated protein FTO is found in parts of the brain that govern energy balance [20] and feeding behaviour [19]; it is encoded by the FTO gene on chromosome 16, and its presence in the hypothalamus is up-regulated following food deprivation. The melanocortin receptor MC4R is encoded by the MC4R gene; studies in mice have shown that its disruption causes hyperphagia, hyperinsulinaemia, and hyperglycaemia [22]. SH2B1 is an adapter protein involved in various signalling pathways; it increases serum levels of leptin [26], and disruption of the SH2B1 gene leads to hunger and insulin resistance. Other genes act peripherally, mainly in adipose tissue. The gene-encoding transcription factor AP2B (TFAP2B), for example, influences glucose transport, lipid accumulation, and adiponectin expression [22], the gene-encoding transcription factor cMAF is involved in adipogenesis [32], and the gene for natural cytotoxicity-triggering receptor 3 (NCR3) probably mediates its effects by causing a low-grade inflammation of adipose tissue [45].
Progressive Loss of Retinal Ganglion Cells in Activating Protein-2β Neural Crest Cell Knockout Mice
Published in Current Eye Research, 2021
Aftab Taiyab, Anthony Saraco, Monica Akula, Paula Deschamps, Alexander K. Ball, Trevor Williams, Judith A. West-Mays
We have previously shown that in the developing murine eye, the transcription factor activating protein 2 (AP-2) is highly expressed in the POM. In particular, two family members, AP-2β (encoded by the gene Tfap2b) and AP-2α (encoded by Tfap2a) are expressed in the POM. At embryonic day 8, (E8) both AP-2β and AP-2α showed overlapping expression in the POM, but by E11 this pattern began to diverge and by E15.5, the POM expressed predominantly AP-2β and very little AP-2.5,6 Thus, AP-2β appears to be the more significant AP-2 family member in the developing POM. Mice with germline deletions of AP-2β (AP-2β−/-) die soon after birth and as a result, full eye development could not be examined.7 Thus, to circumvent the lethality of a germline deletion of the AP-2β transcription factor, our laboratory employed Wnt1-Cre, a Cre well known to be expressed in cranial NCC that contributes, in part, to the development of ocular angle structures and cornea,3 to conditionally delete AP-2β exclusively from the cranial NCCs that contribute to the POM.6 These mice, termed the AP-2β NCC KO, exhibited multiple defects in the developing anterior segment. This included a lack of formation of the corneal endothelium and an anterior iris that was completely adhered to the posterior corneal stroma, resulting in a complete closure of the iridocorneal angle, and absence of formation of the trabecular meshwork and Schlemm’s canal normally found in this region.8 The angle closure was accompanied by a significant increase in intraocular pressure (IOP) in the mutant mice. Importantly, we were also able to demonstrate that the mutant mice exhibited a significant decrease in the number of RGCs by 2–3 months of age, along with evidence of optic nerve degeneration.6