Repeated sequences isolation

Matzke, M.A., Varga, F., Berger, H. et al. (1990). A 41—42 bp tandemly repeated sequence isolated from nuclear envelopes of chicken erythrocytes is located predominantly on microchromosomes. Chromosoma, 99, 131-7. 

Proteins have been isolated from many cereal seeds that have extensive regions of repeating hexa- to nonapeptides. The consensus repeats are rich in Pro and Gin, and always contain an aromatic amino acid, generally Tyr. The CD spectra of fragments of these proteins containing the repeating sequence have been reported (DuPont etal., 2000 Gilbert... 

Nakajima T, Ota N, Kodama T, Emi M. Isolation and radiation hybrid mapping of a highly polymorphic CA repeat sequence at the SREBP cleavage-activating protein (SCAP) locus. J Hum Genet 1999 44 350-351. 

Studies of overall genome composition based on reassociation kinetics (Simpson et ai, 1982 Cox et ai, 1990 Marx et a/., 2000) and analysis of fully sequenced bacterial artificial chromosome (BAC) clones from the 5. mansoni genome project show that platyhelminth genomes contain abundant highly and moderately repetitive sequence (Fig. 2.1). Much of the repetitive DNA comprises two classes of integrated mobile elements class I elements, which include long terminal repeat (LTR) retrotransposons and retroviruses, non-LTR retro-transposons and short interspersed nuclear elements (SINES) and transpose via an RNA intermediate, and class II elements (trans-posons), which transpose as DNA (Brindley et ai, 2003). Additionally, small dispersed or tandemly repeated sequences are common. A wide variety of these sequences have been isolated and characterized from a variety of taxa (Table 2.4). 

In the present discussion, we assume periodic boundary conditions and moreover a situation where there is one more (or one less) atom in the chain than minima in the substrate potential. In the SGE, this translates into a boundary condition where cj) makes a phase shift of 27i as one moves through the periodically repeated sequence. For the energetically most stable solutions, atoms will mostly try to sit at the bottom of the potential. The required phase shift of 271 will occur in a relatively narrow region. Such phase shifts are called walls, discommensurations, or kinks. A representation of a kink is given in Fig. 11. The motion of isolated (and also interacting) kinks under an externally applied force or field is, of course, crucial to friction in the FK model. 

From cartilage, there were isolated two related gjycosaminoglycuronans, chondroitin 4-sulfate (74) and chondroitin 6-sulfate (75), O-sulfated at positions 4 or 6 of the amino sugar component, which in this case is A-acetylgalactosamine. The repeating sequence of chondroitin 6-sulfate may thus be depicted as ... 

Other short repeat sequences have been isolated... 

Lastly, several groups (46-53) have isolated cDNA clones for human von Willebrand s factor (vWf). Again, the predicted amino acid sequence of vWf revealed that 90% of the polypeptide consisted of four types of repeat elements designated A to D. These repeat sequences are unique to vWf except for the A repeat which has limited sequence identity with a region of complement factor B. 

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