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1.
The regions around the human insulin gene have been studied by heteroduplex, hybridization and sequence analysis. These studies indicated that there is a region of heterogeneous length located approximately 700 bp before the 5' end of the gene; and that the 19 kb of cloned DNA which includes the 1430 bp insulin gene as well as 5650 bp before and 11,500 bp after the gene is single copy sequence except for 500 bp located 6000 bp from the 3' end of the gene. This 500 bp segment contains a member of the Alu family of dispersed middle repetitive sequences as well as another less highly repeated homopolymeric segment. The sequence of this region was determined. This Alu repeat is bordered by 19 bp direct repeats and also contains an 83 bp sequence which is present twice. The regions flanking the human and rat I insulin genes were compared by heteroduplex analysis to localize homologous sequences in the flanking regions which could be involved in the regulation of insulin biosynthesis. The homology between the two genes is restricted to the region encoding preproinsulin and a short region of approximately 60 bp flanking the 5' side of the genes.  相似文献   

2.
Structure of the human genomic glutathione S-transferase-pi gene   总被引:6,自引:0,他引:6  
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The structure of the bovine parathyroid hormone (PTH) gene has been analyzed by Southern blot hybridization of genomic DNA and by nucleotide sequence analysis of a cloned PTH gene. In the Southern analysis, several restriction enzymes produced single fragments that hybridized to PTH cDNA suggesting that there is a single bovine PTH gene. The restriction map of the cloned gene is the same as that determined by Southern blot analysis of bovine DNA. The sequence of 3154 bp of the cloned gene has been determined including 510 bp and 139 bp in the 5' and 3' flanking regions, respectively. The gene contains two introns which separate three exons that code primarily for: (i) the 5' untranslated region, (ii) the pre-sequence of preProPTH, and (iii) PTH and the 3' untranslated region. The gene contains 68% A + T and unusually long stretches of 100- to 150-bp sequences containing alternating A and T nucleotides in the 5' flanking region and intron A. The 5' flanking region contains two TATA sequences, both of which appear to be functional as determined by S1 nuclease mapping. Compared to the rat and human genes, the locations of the introns are identical but the sizes differ. Comparable human and bovine sequences in the flanking regions and introns are about 80% homologous.  相似文献   

5.
The objective of this study was to search for polymorphisms and gene regulatory sequences in the 5' flanking region of the sheep insulin-like growth factor I (IGF-I) gene. PCR-SSCP analysis of the 5' flanking region revealed three banding patterns. Family study indicated that these patterns in mixed breed sheep corresponded with three genotypes (with their frequencies in parentheses) AA (0.70), AB (0.25), and BB (0.05), which arose from a one-locus, two allele (A, B) polymorphism. Genotypic frequencies in 22 purebred Polypay sheep were AA (0.77) and AB (0.23). Calculated frequency of the A allele in Polypays was 0.89. No deviation from Hardy-Weinberg equilibrium was detected in this study. Fragments amplified using DNA from homozygous individuals were sequenced and aligned next to each other. A T to C transition and a G to C transversion were found at positions 179 and 181, respectively, of the amplified PCR product, resulting in recognition sites for Bsp143II and HaeI. Analysis of a fragment of 2,162 base pairs upstream of Exon 1, assembled from sheep ESTs and sequence of our amplified PCR products, revealed a promoter sequence approximately 100 bp downstream of the polymorphic sites. The assembled DNA fragment shared 70% sequence homology between sheep and human. These results suggest that sequence of the 5' flanking region of IGF-I gene and location of the IGF-I promoters are similar in human and sheep.  相似文献   

6.
DNA 5' to the human myelin basic protein (MBP) gene, mapped to 18q22----qter, is known to manifest multiallelic DNA length variation with heterozygosity of at least 45%. Isolation of genomic DNA containing the MBP gene first exon and its 5' flanking region reveals that this polymorphism arises from a 994-bp region of the diverged tandem repeat (TGGA)249. This sequence is located from 1082 to 2075 bp upstream of the MBP initiator methionine. The repetitive sequence is 18% diverged from (TGGA)249 and from analysis of higher order subsequence reiterations appears to have undergone extensive recombination. The pattern of higher order repetition suggests that multiple crossover and gene conversion events have occurred within a 1.0-kb region. Molecular clones of this sequence represent essentially the longest allelic form of this region seen in Southern transfer analysis. This repetitive DNA is similar to a sequence 5' to the human myoglobin gene.  相似文献   

7.
Y Tsujimoto  Y Suzuki 《Cell》1979,16(2):425-436
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Isolation and sequencing of mouse angiogenin DNA   总被引:2,自引:0,他引:2  
The mouse genomic DNA for angiogenin, a potent blood vessel inducing protein, has been isolated from a bacteriophage library using the human angiogenin gene as a probe. The 1129 bp fragment contains 499 bp in the 5' flanking region, 192 bp in the 3' flanking region, and 438 bp coding for the mature protein (121 amino acids) and signal peptide (24 amino acids). Potential TATA box and AATAAA polyadenylation sequences are present, and a consensus sequence for an intron 3' boundary occurs 16 bp upstream of the Met-(24) codon, suggesting the presence of an intron in the 5' region. The protein sequence inferred from the DNA is 76% identical to that of human angiogenin, and matches the sequences obtained previously from tryptic peptides of a serum-derived mouse angiogenin. The critical catalytic residues of human angiogenin are conserved in the mouse protein, as are the six cysteines necessary for disulfide bond formation.  相似文献   

10.
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