[Dopamine receptor gene polymorphisms in Guangzhou Hans].

Objective: To determine the distribution of dopamine D2, D3, and D5 receptor(DRD2, DRD3, DRD5) gene polymorphisms in Guangzhou Hans.

Methods: A total of 141 healthy Guangzhou Hans were studied by the use of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and PCR-amplification of specific allele (PASA) techniques. Current results were compared with the data on other ethnic groups.

The C-terminal domain of MutY glycosylase determines the 7,8-dihydro-8-oxo-guanine specificity and is crucial for mutation avoidance.

Escherichia coli MutY is an adenine DNA glycosylase active on DNA substrates containing A/G, A/8-oxoG, or A/C mismatches and also has a weak guanine glycosylase activity on G/8-oxoG-containing DNA. The N-terminal domain of MutY, residues 1-226, has been shown to retain catalytic activity. Substrate binding, glycosylase, and Schiff base intermediate formation activities of the truncated and intact MutY were compared.

[Study on the principles of base change in 4-fold degenerate sites of protein coding genes].

The relationship of transition and transversion of base change in 4-fold degenerate sites of coding genes of 6 proteins, which showed 70% homology in wmposition investigated. Taking into account of the effects of base composition on base substitution, it was found that the transition-transversion bias was evident but not as pronounced as in mitochondrial DNA. Comparison of different kinds of transition or transversion indicated that they happened with rather equal vate, with 0.

Base mismatch-specific endonuclease activity in extracts from Saccharomyces cerevisiae.

An endonuclease activity (called MS-nicking) for all possible base mismatches has been detected in the extracts of yeast, Saccharomyces cerevisiae. DNAs with twelve possible base mismatches at one defined position are cleaved at different efficiencies. DNA fragments with A/G, G/A, T/G, G/T, G/G, or A/A mismatches are nicked with greater efficiencies than C/T, T/C, C/A, and C/C.

Inhibition of autoproteolytic activation of interstitial procollagenase by recombinant metalloproteinase inhibitor MI/TIMP-2.

The purification and cloning of a novel metalloproteinase inhibitor (MI or TIMP-2) related to tissue inhibitor of metalloproteinases (TIMP) has been recently described by our laboratory (DeClerck, Y.A., Yean, T.

Methyl-directed repair of DNA base-pair mismatches in vitro.

An assay has been developed that permits analysis of DNA mismatch repair in cell-free extracts of Escherichia coli. The method relies on repair of heteroduplex molecules of f1 R229 DNA, which contain a base-pair mismatch within the single EcoRI site of the molecule. As observed with mismatch heteroduplexes of lambda DNA [Pukkila, P.