Molecular cloning and functional analysis of the promoter of the human squalene synthase gene

We have cloned and characterized the 5'-flanking region of the gene encoding human squalene synthase. We report here the promoter activity of successively 5'-truncated sections of a 1 kilobase of this region by fusing it to the coding region of a luciferase reporter gene. DNA segments of 200 base pairs (bp) 5' to the transcription start site, as determined by primer extension analysis, show a strong promoter effect on the expression of the luciferase chimeric gene and a high response to the presence of sterols when transiently transfected into the human hepatoma cell line HepG2 or to the hamster-derived CHO-K1 cells. An approximately 50-fold induction of luciferase activity, in the absence of sterols, was observed in transiently transfected HepG2 cells for fusion constructs containing sections of 200, 459, and 934 bp of the putative human squalene synthase promoter. Loss of promoter activity and response to sterols was localized to a 69-bp section located 131 nucleotides 5' to the transcription start site. Sequence analysis of this region showed that it contained a sterol regulatory element 1 (SRE-1) previously identified in other sterol regulated genes (Smith, J. R., Osborne, T. F., Brown, M. S., Goldstein, J. L., and Gil, G. (1988). J. Biol. Chem. 263, 18480-18487) and two potential NF-1 binding sites. Additional CCAAT box, SRE-1 element, and two Sp1 sites were identified 3' to this section. Sequences within this 69-bp DNA, including the SRE-1 cis-acting element, show strong binding to the purified nuclear transcription factor ADD1 (Tonzonoz, P., Kim, J. B., Graves, R. A., and Spiegelman B. M. (1993) Mol. Cell Biol. 13, 4753-4759) by mobility shift assay and footprinting analyses.

[Studies on elastase from Flavobacterium. I. Strain screening and enzyme purification]

132 strains bacteria secreting extracellular elastase were isolated from soil samples, 5 of them possessed considerably high elastiolytic activity of more than 100 u/ml. The highest-yield strain No. 17-87 was characterized as Flavobacterium odoratum, studies on the condition of elastase production revealed that its optimum carbohydrate and nitrogen source were glucose and casein respectively, and that it could utilize fowl ferther meal and wheat bran to give 80% relative yield. The culture exhibited maximum elastase activity at 26 degrees C for 21 hours, the productivity could be increased when the aeration was improved. The PAGE-homogenous elastase preparation was obtained from the culture broth by (NH4)2SO4 fractionation, DEAE-cellulose column chromatography and gel filtration on Sephadex G-75. The molecular weight was determined to be 21380 by SDS-PAGE, the elastiolytic activity was optimal at pH7.4 and 50 degrees C. The enzyme was stable over the range of pH4.5-9.5 and below 40 degrees C, but the activity was inhibited completely by Fe3+, Zn2+, Cu2+, Cr3+, Co2+, Ni2+, Hg2+, Ag+.

[Statistical analysis of age-related macular degeneration (AMD) in the differentiation of symptoms and signs]

Ninety-eight individuals according with entry criterion were allowed to participate in the study. Their clinical symptoms and signs were classified to seven symptoms by means of epidemiology. The results indicated syndrome of vital energy in patient group had more significant than controlled group, the others had not. In the syndrome of deficiency of vital energy, the frequency that the corpalent tongue or margin and tip of the tongue look jagged and the pulse lost its vitality emerged in the patient group surpassed significantly the controlled group. So, we initially considered that traditional Chinese medicine syndrome of AMD patient is mainly the deficiency of vital energy. The happening and development of AMD is probably related to the physique of deficiency of vital energy, it is a key point of determination of treatment with traditional chinese medicine based on differentiation of symptoms and signs.