imagine (Institute of molecular genetics and genetic engineering)
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Properties of in vitro constructed DNA elements responsible for gene activity cloned in Escherichia coli – properties of new PLtl promoter
No full textКонструисан је нови PLtl промотор који је састављен од оператора и промоторских секвенци tac и –35 do -135 региона PL промотора фага ʎ који садржи АТ богати регион, као и OL2 и OL3 регионе .Поређене су транскрипционе особине са tac i P помотором. PLtl промотор поседује следеће особине: (i) када је под репресијом експресија гена је занемарљива; (ii) након индукције PLtl промотер показује 1.4 – 2 пута већу активностt; (iii) PLtl промотор омогућава контролу репресора и тиме омогућује успешну експресију производа непознатих карактеристика.The newly constructed PLtl hybrid promoter is composed of the operator and promoter sequences of tac and the -35 to -135 region of the phage lambda PL promoter, which contains the AT-rich block and the OL2 and OL3 segments. Transcriptional properties of PLtl were examined and compared with tac and lambda PL as reference promoters. The hybrid PLtl exhibits different and improved properties over tac promoter in four ways: (i) when repressed, the repression is almost complete; (ii) after complete induction, the hybrid PLtl promoter shows a 1.4-2 times higher expression; (iii) the hybrid PLtl promoter permits flexible gene expression because it can be utilized under either or both repression controls simultaneously; (iv) the PLtl promoter permits enhanced expression of genes encoding products with unknown properties
Cellular role of DNA polymerase I
No full textEscherichia coli possesses three well‐established DNA polymerases, I, II and III. DNA polymerase I (Pol 1) is the main repair polymerase in E. coli and also has a minor but important role in chromosomal replication. A major advantage of Pol I as an experimental system is its simplicity: unlike other replication enzymes, it is active as a single subunit. To a large extent, mutagenesis appears to be the result of (dis) functions of the DNA replication machinery. It is the purpose of this review to provide an integrated view of this relationship with particular emphasis on the role of Pol I in mutagenic events. Copyrigh
Nucleotide and amino acid polymorphism in the gene for L-histidinol dehydrogenase of Escherichia coli K12
Full text linkOrigin of rat β-globin haplotypes containing three and five genes
Full text linkWe have reported in rat three adult β-gene haplotypes containing either five or three genes. Detailed sequence analysis reveals that the leftmost gene is the major gene and that at the opposite end downstream lies the minor gene. All of the genes lying between them are minor-major hybrids indicating their origin by unequal crossing-over. In two haplotypes β-globin genes were found with an L1 element inserted directly into IVS2. The described results allow the formulation of a pathway of mutational events leading from the ancient two-β-gene rodent ancestor through a three-gene haplotype to five-gene haplotypes, one of which is postulated to have arisen in common laboratory strains since their capture in the wild.[https://academic.oup.com/mbe/article/7/5/407/1061225
Variant chromosomal arrangement of adult β-globin genes in rat
No full textThe genomic organization of three haplotypes of β-globin genes was determined to resolve the question of the number of those genes in rat. Haplotype a, found in inbred strain DA, has three genes or pseudogenes, while haplotypes b, found in AO, Y5 and Wistar strains, and c, found in Wistar strain, have five genes or pseudogenes each. In haplotypes b and c, the first gene is of βmajor type and the remaining four are of βminir type. Partial sequencing of six out of 13 genes shows that duplications of βminor genes are causing polymorphism in a number of genes. Also, in haplotype b two βminor genes have a 6.5-kb intron 2, while in haplotype c only one βminor gene contains such a large intron 2. The three structurally different haplotypes described are not interconvertible by single recombination events. The results indicate that the rat has the highest number of adult β-globin genes found in mammals so far
Limited polymorphism of both classes of MHC genes in four different species of the Balkan mole rat
No full textWe analyzed the restriction fragment length polymorphism of class I and class II MHC genes in DNA from 20 individuals belonging to the four different species of the complex of species of Balkan mole rats Spalax leucodon captured at four different localities in Yugoslavia. All populations were tested with four restriction enzymes and one conserved mouse probe for each of the two classes of MHC genes. The probes employed detect either limited polymorphism of class I genes or lack of polymorphic bands containing class II genes. Of the two other subterranean rodents that have been studied, four karyotype forms of the Israeli mole rat show polymorphism in both classes of MHC genes similar to the one found in all other mammals (Nižetić et al. 1985), and the Syrian hamster shows limited polymorphism of class I genes and high polymorphism of class II genes (McGuire et al. 1985). Balkan mole rats belong to a new group in this respect, different from all mammals studied so far, since they apparently show limited polymorphism of both classes of MHC genes
