Diss. (sammanfattning) Stockholm : Karol. inst. / Härtill 4 uppsatser.

Amyotrophic lateral sclerosis (ALS) is a devastating motor neuron disease which results from the degeneration of upper and lower motor neurons in the brainstem, spinal cord and motor cortex. Tragically there is no treatment to prevent ALS. The drug Riluzole acts to delay progression, but only by a month or so in this disease that has a survival length of three to five years. The identification of genes that are mutated in patients with ALS would help devise novel therapeutic strategies as much remains to be discovered about the genetics of ALS. Familial forms of the disease account for only 5-10% of patients. Among these familial cases, about 15-20% are caused by mutations in the zinc/copper superoxide dismutase gene, but the genetic basis of the remaining familial cases and the many sporadic cases continues to be largely unknown. / Altogether, the results presented in this thesis came from the use of several strategies to establish the genetic cause of ALS and the related motor neuron disorders like hereditary spastic paraplegia (HSP) and primary lateral sclerosis (PLS). A concerted and collaborative effort was put forth to identify the gene causative for ALS3 on chromosome 18. In addition, a recently reported locus has been confirmed on chromosome 9p for patients that present both ALS and frontotemporal dementia. The major finding involves the discovery of eight mutations in the TARDBP gene in nine patients with sporadic and familial ALS. Furthermore, a large association study evaluated the role of common polymorphisms in the paraoxonase gene cluster in susceptibility to the development of ALS. In the analysis of upper motor neuron diseases, mutations in a novel gene, KIAA0196, were identified for the HSP locus SPG8 on chromosome 8. Finally, the first locus for PLS was discovered on the p-arm of chromosome 4 following genome scan analysis of a large Quebec family with PLS. / These genetic discoveries all contributed novel advances to the field of motor neuron disorders. As more is elucidated regarding the biochemical function of these the proteins encoded by these genes, a more comprehensive picture of ALS and other motor neuron disorders will hopefully emerge.

No description available.

In mammals, circadian rhythms are generated by transcriptional-translational feedback loops consisting of a set of clock genes and their protein products. Among them, Bmal1 is a critical clock gene in generating and maintaining circadian rhythms. Moreover, orphan nuclear receptors REV-ERBs and RORs were known to respectively repress and activate Bmal1 transcription. In our study, we further demonstrated that: (1) REV-ERBalpha might be the main regulator in maintaining Bmal1 oscillation in thymus. (2) Rorgamma mRNA is constant in muscle and testis, and rhythmic in liver, while Rorgammat mRNA is only expressed in thymus, at constant levels. Moreover, the expressions of these two Rorgamma isoforms are affected in Clock mutant mice in a distinct way. (3) RORgamma and RORgammat can activate Bmal1 transcription at a similar level. (4) Rorgamma is a clock-controlled gene. Altogether, our results suggest that the crucial role of REV-ERBs and RORs in peripheral clocks. Furthermore, our work highlights functional differences among mammalian peripheral clocks, which provides important insights into the complexity of the circadian system.

No description available.