László Sipos

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A very large cis-regulatory region of approximately 300 kb is responsible for the complex patterns of expression of the three homeotic genes of the bithorax complex Ubx, abd-A and Abd-B. This region can be subdivided in nine parasegment-specific regulatory subunits. Recent genetic and molecular analysis has revealed the existence of two novel cis-regulatory(More)
The applicability of the mixed bacterial culture, originated from two-stage anaerobic-aerobic industrial yeasts production wastewater treatment plant for high rate denitrification processes was investigated. After acclimation to nitrate, the dominant strains were Pseudomonas and Paracoccus sp. Complete denitrification with low accumulation of nitrite-N (0.1(More)
The three homeotic genes of the bithorax complex (BX-C), Ubx, abd-A and Abd-B control the identity of the posterior thorax and all abdominal segments. Large segment-specific cis-regulatory regions control the expression of Ubx, abd-A or Abd-B in each of the segments. These segment-specific cis-regulatory regions span the whole 300 kb of the BX-C and are(More)
Two antagonistic groups of genes, the trithorax- and the Polycomb-group, are proposed to maintain the appropriate active or inactive state of homeotic genes set up earlier by transiently expressed segmentation genes. Although some details about the mechanism of maintenance are available, it is still unclear how the initially active or inactive chromatin(More)
Results of our investigations during the last five years are summarized. The concentrations of Cd, Pb and Cu have been determined in coastal areas of the Western Mediterranean and the North Sea, reflecting the influence of the pollution sources along the shore line. Deep sea water and surface water sample from the Pacific, Atlantic, Mediterranean and Arctic(More)
Abdominal-B (Abd-B) is a complex homeotic gene with a difficult task: one transcript determines the identity of four different abdominal segments throughout development in Drosophila. Although an increasing amount of information is available about the structure and the functioning of the regulatory regions that determine the expression pattern of Abd-B, it(More)
The Abd-B gene, one of the three homeotic genes in the Drosophila bithorax complex (BX-C), is required for the proper identity of the fifth through the eighth abdominal segments (corresponding to parasegments 10-14) of the fruitfly. The morphological difference between these four segments is due to the differential expression of Abd-B, which is achieved by(More)
The homeotic genes controlling segment identity in Drosophila are repressed by the Polycomb group of genes (PcG) and are activated by genes of the trithorax group (trxG). An F(1) screen for dominant enhancers of Polycomb yielded a point mutation in the heat shock cognate gene, hsc4, along with mutations corresponding to several known PcG loci. The new(More)
Long-term repression of homeotic genes in the fruit fly is accomplished by proteins of the Polycomb Group, acting at Polycomb response elements (PREs). Here we use gene conversion to mutate specific DNA motifs within a PRE to test their relevance, and we exchange PREs to test their specificity. Previously we showed that removal of a 185 bp core sequence(More)