[New polymorphic variants of the gene for human blood coagulation factor IX]. / Novye polimorfnye varianty gena faktora IX svertyvaemosti krovi cheloveka.

The polymorphism of Alu-repeats, which are located in the introns of the human factor IX gene (copies 1-3), was studied. To identify polymorphic variants, direct sequencing of PCR products that contained appropriate repeats was used. In each case, 20 unrelated X chromosomes were studied. A polymorphic Dra I site was found near the 3'-end of Alu copy 3 within the region of the polyA tract. A PCR-based testing system with internal control of restriction hydrolysis was suggested. Testing 81 unrelated X chromosomes revealed that the frequency of the polymorphic Dra I site is 0.23. Taq I polymorphism, which was revealed in Alu copy 4 of factor IX gene in our previous work, was found to be closely linked to Dra I polymorphism. Studies in linkage between different types of polymorphisms of the factor IX gene revealed the presence of a rare polymorphism in intron A that was located within the same minisatellite region as the known polymorphic insertion 50bp/Dde I. However, the size of the insertion in our case was 26 bp. Only one polymorphic variant was found among over 150 unrelated X chromosomes derived from humans from Moscow and its vicinity.

[New site-specific endonucleases from strains of Bacillus]. / Novye sait-spetsificheskie éndonukleazy iz shtammov Bacillus.

In a search for new restriction endonucleases type II, among forty bacterial strains of the Bacillus genus two strains producing site-specific endonucleases have been found. Endonucleases BbvAIII and BspFI, isolated from B. brevis BLM B-677 and B. species F, are shown to be true isoschisomers of BspMII (Kpn2I) and Sau3AI, respectively.

[Use of the polymerase chain reaction to detect beta-thalassemia mutations in heterozygous carriers from Azerbaijan while performing prenatal DNA-diagnosis]. / Ispol'zovanie polimeraznoi tsepnoi reaktsii dlia vyiavleniia beta-talassemicheskikh mutatsii u geterozygotnykh nositelei iz Azerbaidzhana pri provedenii prenatal'noi DNK-diagnostiki.

Prenatal DNA-diagnosis of beta-thalassemia in a family from Azerbaijan revealed two mutations new for this region--G-A transition at codon 15 and G-C transversion at position 5 of the intron 1. Prenatal diagnosis was carried out by direct sequencing of in vitro amplified (PCR) beta-globin gene fragments with a modified Sanger technique using thermostable DNA polymerase. The absence of parents mutations in the fetal DNA allowed us to conclude that the fetus is normal. The diagnosis was proved at hematological testing of the baby borne.

[Artificial DNA splicing using directed ligation]. / Iskusstvennyi splaising DNK s pomoshch'iu napravlennogo ligirovaniia.

An approach to the directed genetic recombination in vitro has been devised, which allows for joining, in a predetermined chemical-enzymatic way, a series of DNA segments to give a precisely spliced polynucleotide sequence (DNA Splicing by Directed Ligation, SDL). The approach makes use of amplification, by several polymerase chain reactions (PCR), of the chosen DNA segments. The corresponding primers contain recognition sites of the class IIS restriction endonucleases, yielding protruding ends of unique primary structures. The protruding ends of the segments to be joined together are structurally predetermined to make them mutually complementary. Ligation of the mixture of the segments so synthesized gives the desired sequence in an unambiguous way. The suggested approach has been exemplified by the synthesis of a totally processed (intronless) gene encoding human mature interleukin-1 alpha.

A modified approach to identification of the sickle cell anemia mutation by means of allele-specific polymerase chain reaction.

The allele-specific PCR approach has been modified by introducing a second mismatch at the 3'-penultimate link of the primer and used to identify the sickle cell anemia mutation (A-->T transversion in the sixth codon of the human beta-globin gene causing Glu-->Val substitution in the protein), thus obviating the problem of an interpretationally ambiguous 3'-terminal mismatch including T residue.

Method of artificial DNA splicing by directed ligation (SDL).

An approach to directed genetic recombination in vitro has been devised, which allows for joining together, in a predetermined way, a series of DNA segments to give a precisely spliced polynucleotide sequence (DNA splicing by directed ligation, SDL). The approach makes use of amplification, by means of several polymerase chain reactions (PCR), of a chosen set of DNA segments. Primers for the amplifications contain recognition sites of the class IIS restriction endonucleases, which transform blunt ends of the amplification products into protruding ends of unique primary structures, the ends to be used for joining segments together being mutually complementary. Ligation of the mixture of the segments so synthesized gives the desired sequence in an unambiguous way. The suggested approach has been exemplified by the synthesis of a totally processed (intronless) gene encoding human mature interleukin-1 alpha.

Synthesis and modification of genes through artificial splicing by directed ligation (ASDL).

An approach to the directed genetic recombination in vitro mediated by synthetic oligodeoxynucleotides and polymerase chain reaction (PCR) is devised, which allows the joining, in a predetermined chemical-enzymatic way, of a series of DNA segments to give a precisely spliced polynucleotide sequence (Artificial Splicing by Directed Ligation, ASDL). The approach can thus lead to the totally processed eukaryotic genes using genomic DNA, with no mRNA needed. This approach has been used for the synthesis of artificial genes of interleukin-1 alpha and, in combination with PCR on the mRNA-cDNA duplex as template, of interleukin-1 receptor antagonist and their analogues, as well as for the modified genes.

Molecular nature of mutations causing beta zero-thalassaemia in Azerbaijan.

Beta zero-thalassaemia comprises a series of closely related haemoglobinopathies which are widely spread in some areas (the Mediterranean, Caucasus, Central Asia, and others). It is caused by a variety of mutations in the beta-globin gene which damage its expression, thus leading to severe illness, which is often lethal at an early age. By means of the polymerase chain reaction (PCR), restriction analysis, and sequencing by the Maxam-Gilbert method, we have identified a number of mutations in the beta-globin gene that cause beta zero-thalassaemia in the Azerbaijanian population, viz AA deletion in codon 8, C----T transition in codon 39, and a previously unknown G deletion in codons 82/83.

[Identification of a nature of mutation in the 12th exon of phenylalanine hydroxylase gene in patients with phenylketonuria]. / Opredelenie prirody mutatsionnogo povrezhdeniia v 12-om ékzone fenilalaningidroksilaznogo gena u bol'nykh fenilketonuriei.

Upon amplification in vitro of the 12th exon area of the human phenylalanine hydroxylase gene followed by allele-specific hybridisation of the amplification product with synthetic probes and its sequencing by the Maxam-Gilbert method, a C----T transition causing phenylketonuria has been identified in Latvian patients.