Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P50583 (asymmetrical)
 12,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The distribution of somatic hypermutations around the rearranged V(D)J in antigen-selected B cells is asymmetrical. At the 5' end of the gene a high frequency of mutations does not occur until approximately 200 bp downstream of the V gene promoter in the leader intron. This finding seems inconsistent with recently proposed, transcription-coupled models of hypermutation. Here we describe studies on extensively mutated copies of a kappa light chain transgene which appear to exist as passenger genes for a significant portion of their mutational history. These transgenes contain between one and four in-frame stop codons, and have a ratio of replacement to silent mutations in framework regions that is near random; the ratio in their functional counterparts is clearly non-random. When non-functional passenger and functional transgenes are compared, the patterns of mutation in the leader intron are not significantly different; the frequency 3' is greater in the passenger transgenes. This result indicates that the low level mutational activity immediately 3' of the promoter followed by rapid rise in activity is an intrinsic feature of the mutational process. One inference from this finding is that there is a structural feature in V region DNA or one induced during transcription which is critical to a functioning mutator.
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PMID:Promoter-associated displacement of hypermutations. 972 99

The genetically hypothyroid mouse, Tshr(hyt), has a single point mutation resulting in a defective thyroid-stimulating hormone receptor, and therefore a non-functional thyroid gland. This is an autosomal recessive disorder and affected mice have been reported to have a number of somatic and behavioral deficits. This study reports a pronounced, spontaneous, asymmetrical circling behavior in the Tshr(hyt) mouse. The spontaneous circling behavior appeared in about 25% of the homozygous animals, in both males and females. The circling usually appeared by postnatal day 35 and continued throughout the lifespan of the animal. The circling was in one direction only, either clockwise or counterclockwise, with the directional preference being almost absolute. A stereological analysis of tyrosine hydroxylase immunoreactive neurons in the substantia nigra and adjacent ventral tegmental area of circling homozygous mice, non-circling homozygous mice and heterozygous mice revealed that the circlers had significantly fewer (40% reduction) midbrain dopamine neurons than those animals that did not circle. There was not an association between the direction of the circling and an asymmetry in the number of dopamine neurons in the midbrains of these mice. There was no difference in the number of dopamine neurons in the midbrain of the homozygous non-circlers and the heterozygous mice. These studies indicate that about 25% of genetically hypothyroid mice demonstrated a spontaneous, perseverative, unilateral circling behavior that was associated with a significant reduction in the number of their midbrain dopamine neurons. Thus congenitally hypothyroid mice are at risk for a reduction in the number of nigral dopamine neurons and an associated repetitive movement disorder.
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PMID:Spontaneous circling behavior and dopamine neuron loss in a genetically hypothyroid mouse. 1153 Feb 27

This paper describes tooth development in a basal squamate, Paroedura picta. Due to its reproductive strategy, mode of development and position within the reptiles, this gecko represents an excellent model organism for the study of reptile development. Here we document the dental pattern and development of non-functional (null generation) and functional generations of teeth during embryonic development. Tooth development is followed from initiation to cytodifferentiation and ankylosis, as the tooth germs develop from bud, through cap to bell stages. The fate of the single generation of non-functional (null generation) teeth is shown to be variable, with some teeth being expelled from the oral cavity, while others are incorporated into the functional bone and teeth, or are absorbed. Fate appears to depend on the initiation site within the oral cavity, with the first null generation teeth forming before formation of the dental lamina. We show evidence for a stratum intermedium layer in the enamel epithelium of functional teeth and show that the bicuspid shape of the teeth is created by asymmetrical deposition of enamel, and not by folding of the inner dental epithelium as observed in mammals.
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PMID:Tooth development in a model reptile: functional and null generation teeth in the gecko Paroedura picta. 2278 Jan 1