Tandem repeat

Leucine residues 2, 5, 7, 12, 20, and 24 of the motif are invariant in both type A and type B repeats of the ribonuclease inhibitor. An examination of more than 500 tandem repeats from 68 different proteins has shown that residues 20 and 24 can be other hydrophobic residues, whereas the remaining four leucine residues are present in all repeats. On the basis of the crystal structure of the ribonuclease inhibitor and the important structural role of these leucine residues, it has been possible to construct plausible structural models of several other proteins with leucine-rich motifs, such as the extracellular domains of the thyrotropin and gonadotropin receptors. 

The retinoid X receptor forms heterodimers that recognize tandem repeats with variable spacings... 

Short (2-6 bp), inherited, tandem repeat units of DNA occur about 50,000-100,000 times in the human genome (Chapter 36). Because they occur more frequently—and in view of the routine application of sensitive PCR methods—they are replacing RFLPs as the marker loci for various genome searches. 

The genes encoding the polypeptide backbones of a number of mucins derived from various tissues (eg, pancreas, small intestine, trachea and bronchi, stomach, and salivary glands) have been cloned and sequenced. These studies have revealed new information about the polypeptide backbones of mucins (size of tandem repeats, potential sites of N-glycosylation, etc) and ultimately should reveal aspects of their genetic control. Some important properties of mucins are summarized in Table 47-8. 

Telomeres are the nucleoprotein assembUes at the ends of chromosomes that comprise guanine-rich tandem-repeating DNA sequences (the size of a typical telomere is aroimd 6-12 kb in length in hiunans) together with a number of structural and regulatory proteins. The major function of telomeres is to protect chromosome ends from base-pair loss and end-to-end fusions, thereby safeguarding the integrity of each chromosome [10, llj. The enzyme... 

Kasai K, Nakamura Y and White R 1990) Amplification of a variable number of tandem repeats (VNTR) locus (pMCTii8) by the polymerase chain reaction (PCR) and its application to forensic science. ] For Sci 35 1196-1200. 

The linear RCA method can use both target and signal amplification. A DNA circle (such as a plasmid, circular vims or circular chromosome) is amplified by polymerase extension of a complementary primer. Up to 10 tandemly repeated, concantemerized copies of the DNA circle are generated by each primer, resulting in one single-stranded, concantemerized product. ... 

Baba, Y., Tomisaki, R., Sumita, C., Morimoto, I., Sugita, S., Tsuhako, M., Miki, T., and Ogihara, T., Rapid typing of variable number of tandem repeat locus in the human apolipoprotein B gene for DNA diagnosis of heart disease by polymerase chain reaction and capillary electrophoresis, Electrophoresis, 16, 1437, 1995. 

Schmalzing, D., Koutny, L., Chisholm, D., Adourian, A., Matsudaira, P, and Ehrlich, D., Two-color multiplexed analysis of eight short tandem repeat loci with an electrophoretic microdevice, Anal. Biochem., 270, 148, 1999. 

Ito, K. et al. (2002). A variable number of tandem repeats in the serotonin transporter gene does not affect the antidepressant response to fluvoxamine. Psychiatry Res, 111, 235-9. 

Miller J. L., Lyle V. A., Cunningham D. Mutation of leucine-57 to phenylalanine in a platelet glycoprotein Iba leucine tandem repeat occurring in patients with an autosomal dominant variant of Bemard-Soulier disease. Blood 1992 79,439-46. 

In protozoa this problem is solved by the addition of preexisting oligodeoxynucleotide blocks to the 3 ends of DNA. These blocks are composed of tandemly repeated units of (T2G4)n or (T4G4)n, where n is approximately 50. The enzyme that adds these polymers requires a primer but not a template. These oligonucleotide block polymers are called telomers. Another DNA polymerase,... 

Tweedie, S., Paxton, W.A., Ingram, L., Maizels, R.M., McReynolds, L.A. and Selkirk, M.E. (1993) Brugia pahangi a surface-associated glycoprotein (gpl5/400) is composed of multiple tandemly repeated units and processed from a 400-kDa precursor. Experimental Parasitology 76, 156-164. 

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