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The myc family of proto-oncogenes consists of several members that possess regions of sequence homology and some have known similarities in structure and function. We have isolated an 8.8-kb EcoRI fragment from a human genomic library by hybridization to a 28-base oligonucleotide probe derived from a region of the second exon of MYC, which is highly conserved in the myc gene family. Sequence analysis of this myc-like (MYCLK1) DNA fragment has revealed the existence of a region with 85% homology to the 28-base oligonucleotide probe. An open reading frame of 207 nucleotides containing the region of homology was found. We have mapped MYCLK1 to human chromosome 7 at band p15 by chromosome in situ hybridization; this site is distinct from the map location of previously characterized myc genes. Whether MYCLK1 represents a new functional member of the myc family of proto-oncogenes remains to be determined. 相似文献
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Morton Beiser 《Culture, medicine and psychiatry》1987,11(4):437-464
Little is known about the psychological mechanisms people employ in adapting to extreme circumstances such as becoming refugees. Case studies of refugees making up part of a sample of 1348 persons relocated from Southeast Asia to Vancouver, British Columbia, suggest that altering one's perception of time may be an adaptive strategy. During periods of acute stress, refugees seem to focus on the present to the relative exclusion of past and future. The reemergence of past and future into consciousness brings about a risk for developing depression. Epidemiological data corroborate inferences from case material, demonstrating that refugees are more present-oriented than the indigenous population. A Nostalgic time orientation, preoccupation with the past, is associated with elevated depression scores. Contrasts are drawn between nostalgia, a maladaptive pattern, and memory, which is an inevitable part of the process of personality integration. 相似文献
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J R Bloomer H D Hill K O Morton L A Anderson-Burnham J G Straka 《The Journal of biological chemistry》1987,262(2):667-671
Ferrochelatase was purified from the livers of normal and protoporphyria cattle by chromatography on Blue Sepharose CL-6B in order to investigate the enzyme defect in this disorder. The increase in specific activity (up to 2900-fold) indicated that the normal and protoporphyria enzymes were purified to a similar degree. The mutant enzyme had catalytic activity which was 10 to 15% of normal ferrochelatase, although the Michaelis constants for protoporphyrin and iron were similar. The molecular mass of the normal and protoporphyria enzyme protein was 40 kDa as evaluated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). In the presence of 15 mM sodium cholate, gel filtration demonstrated a similar size. However, at a lower concentration of sodium cholate (4 mM) the molecular mass was about 240 kDa, suggesting that the purified enzymes aggregate under this condition. Polyvalent antibodies were raised in rabbits using as antigens purified normal native enzyme and normal 40-kDa protein which had been further purified by preparative SDS-PAGE. In Western blots these antibodies complexed with both the normal and mutant 40-kDa proteins. The amount of 40-kDa protein in normal and protoporphyria mitochondrial fractions was also similar as evaluated by Western blots. These studies indicate that the ferrochelatase defect in bovine protoporphyria probably results from a point gene mutation that causes a minor change in enzyme structure. 相似文献
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Localization of the alpha 1 and alpha 2 subunits of the dihydropyridine receptor and ankyrin in skeletal muscle triads 总被引:8,自引:0,他引:8
We have studied the subcellular distribution of the alpha 1 and alpha 2 subunits of the dihydropyridine (DHP) receptor and ankyrin in rat skeletal muscle with immunofluorescence and immunogold labeling techniques. All three proteins were concentrated in the triad junction formed between the T-tubules and sarcoplasmic reticulum. The alpha 1 and alpha 2 subunits of the DHP receptor were colocalized in the junctional T-tubule membrane, supporting their proposed association in a functional complex and the possible participation of the alpha 2 subunit in excitation-contraction coupling. Ankyrin label in the triad showed a distribution different from that of the DHP receptor subunits. In addition, ankyrin was found in longitudinally oriented structures outside the triad. Thus, ankyrin might be involved in organizing the triad and in immobilizing integral membrane proteins in T-tubules and the sarcoplasmic reticulum. 相似文献
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Human corticotropin releasing hormone gene is located on the long arm of chromosome 8 总被引:4,自引:0,他引:4
The chromosomal locus of the human corticotropin releasing hormone (hCRH) gene was assigned to chromosome 8 using Southern blot analysis of human x rodent cell hybrids and was localized to band 8q13 using in situ hybridization to metaphase chromosomes. The absence of secondary hybridization strongly suggests that hypothalamic and placental CRH are transcribed from the same gene. 相似文献