IDENTIFICATION AND CHARACTERIZATION OF A NEW GENE FROM HUMAN-CHROMOSOME-21 BETWEEN MARKERS D21S343 AND D21S268 ENCODING A LEUCINE-RICH PROTEIN

We initiated the present work as part of an effort to identify and cha racterize genes from the EST2-HMG14 region from human chromosome 21 po tentially responsible for some of the Down syndrome (DS) features. Gen omic sample sequencing with cosmid clone A1047 located in the ETS2-HMG 14 region of chromosome 21 has led to the identification and sequencin g of a novel 1080-bp cDNA. This cDNA contains a potential ORF of 867 b p predicting a 288-amino-acid protein rich in leucine with a molecular weight of 32.8 kD. Northern blot analysis and RT-PRC indicate that th e expression of this novel gene is high in testis and in the human leu kemic T cell line Jurkat and lower in other tissues including all feta l tissues studied. We have called to this novel gene c21-LRP (chromoso me 21 leucine-rich protein) and, because of its location in the DS-2 r egion, it could be a candidate for some of the DS anomalies. Mapping e xperiments have narrowed the location of the c21-LRP gene between mark ers D21S343 and D21S268 from chromosome 21. Analysis of the c21-LRP pr otein predicts two transmembrane helices and detects several signature s and potential homologies to known proteins pointing toward several p otential roles for this protein. (C) 1998 Academic Press.