Interchromosomal associations between alternatively expressed loci

The T-helper-cell 1 and 2 (T(H)1 and T(H)2) pathways, defined by cytokines interferon-gamma (IFN-gamma) and interleukin-4 (IL-4), respectively, comprise two alternative CD4+ T-cell fates, with functional consequences for the host immune system. These cytokine genes are encoded on different chromosomes. The recently described T(H)2 locus control region (LCR) coordinately regulates the T(H)2 cytokine genes by participating in a complex between the LCR and promoters of the cytokine genes Il4, Il5 and Il13. Although they are spread over 120 kilobases, these elements are closely juxtaposed in the nucleus in a poised chromatin conformation. In addition to these intrachromosomal interactions, we now describe interchromosomal interactions between the promoter region of the IFN-gamma gene on chromosome 10 and the regulatory regions of the T(H)2 cytokine locus on chromosome 11. DNase I hypersensitive sites that comprise the T(H)2 LCR developmentally regulate these interchromosomal interactions. Furthermore, there seems to be a cell-type-specific dynamic interaction between interacting chromatin partners whereby interchromosomal interactions are apparently lost in favour of intrachromosomal ones upon gene activation. Thus, we provide an example of eukaryotic genes located on separate chromosomes associating physically in the nucleus via interactions that may have a function in coordinating gene expression.     

A selective de-heparinizer filter made of new cross-linked polymers of a poly-amido-amine structure

Riassunto Dae polimeri reticolati di nuova sintesi, contenenti gruppi amminici terziari, sono in grado di assorbire selettivamente eparina dal sangue. Essi non sono emolitici e non interferiscono con i fattori della coagulazione.

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Acknowledgment. This work was supported by the Programma Speciale Technologie Biomediche of the Italian National Council of Researches.     

Paper electrophoresis separation of the soluble proteins of rat muscle sarcosomes

Riassunto Viene descritta la presenza, nel succo dei sarcosomi del muscolo di ratto, di 4 componenti proteici separabili mediante elettroforesi su carta. I 4 componenti sono rappresentati nella misura di rispettivamente 26.1, 18.4, 33.2 e 22.3 per 100 delle proteine totali.     

Genetic diversity of rhizobial populations recovered from three Lotus species cultivated in the infra-arid Tunisian soils

gments from each strain based on the UPGMA algorithm from the combined patterns showed that Lotus isolates are very diverse and that they were affiliated to Sinorhizobium,Rhizobium,and Mesorhizobium genera.     

Purification et cristallisation de 1'α-amylase de bactérie

Summary The purification and crystallization of bacterial -amylase are described. It is not identical with pancreas -amylase, but its action on starch is the same.