Anti-PFKL (full length) polyclonal antibody

The construction of a transcriptional map for human chromosome 21 requires the generation of a specific catalogue of genes, together with corresponding mapping information. Towards this goal, we conducted a pilot study on a pool of random chromosome 21 cosmids representing 2 Mb of non-contiguous DNA. Exon-amplification and cDNA selection methods were used in combination to extract the coding content from these cosmids, and to derive expressed sequences libraries. These libraries and the source cosmid library were arrayed at high density for hybridisation screening. A strategy was used which related data obtained by multiple hybridisations of clones originating from one library, screened against the other libraries. In this way, it was possible to integrate the information with the physical map and to compare the gene recovery rate of each technique. cDNAs and exons were grouped into bins delineated by EcoRI cosmid fragments, and a subset of 91 cDNAs and 29 exons have been sequenced. These sequences defined 79 non-overlapping potential coding segments distributed in 24 transcriptional units, which were mapped along 21q. Northern blot analysis performed for a subset of cDNAs indicated the existence of a cognate transcript. Comparison to databases indicated three segments matching to known chromosome 21 genes: PFKL, COL6A1 and S100B and six segments matching to unmapped anonymous expressed sequence tags (ESTs). At the translated nucleotide level, strong homologies to known proteins were found with ATP-binding transporters of the ABC family and the dihydroorotase domain of pyrimidine synthetases. These data strongly suggest that bona fide partial genes have been isolated. Several of the newly isolated transcriptional units map to clinically important regions, in particular those involved in Down's syndrome, progressive myoclonus epilepsia and auto-immune polyglandular disease. The study presented here illustrates the complementarity of exon-amplification and cDNA selection techniques for generating a large resource of new expressed landmarks, which contribute to the construction of a chromosome 21 transcript map.

One hundred progeny from each of two intersubspecific mouse backcrosses were used to construct a comparative genetic map of a region of mouse chromosome 10 (MMU10) that is homologous to the distal tip of the long arm of human chromosome 21 (HSA21). The analysis included five genes and three simple sequence repeat markers, two of which flanked the HSA21-homologous cluster on either side. Analysis of 200 backcross progeny detected at least one crossover between each pair of adjacent genes and demonstrated that the proximal to distal orientation of the cluster was reversed between human and mouse. The order was determined to be Fyn-1-D10Mit20-S100b-Col6a1-Itgb2-Pfkl/D10Mit7-D10Mit11. Comparative mapping supports the order of corresponding markers on HSA21 determined using pulsed-field gel electrophoresis and radiation hybrid line data. However, sequence tagged site content mapping of human yeast artificial chromosomes (YACs) yielded conflicting data on the relative positions of human COL6A1 and S100B on HSA21. This discrepancy was resolved here by demonstrating that several key YACs used in the human contig analysis were mistyped for S100B. The murine map reported here provides a scaffold for construction of physical maps and yeast artificial chromosome contigs that will be useful in the development of mouse models for the study of Down syndrome. (C) 1994 Academic Press, Inc.