Identification and characterization of a new gene from human chromosome 21 between markers D21S343 and D21S268...

We initiated the present work as part of an effort to identify and characterize genes from the EST2-HMG14 region from human chromosome 21 potentially responsible for some of the Down syndrome (DS) features. Genomic sample sequencing with cosmid clone A1047 located in the ETS2-HMG14 region of chromosome 21 has led to the identification and sequencing of a novel 1080-bp cDNA. This cDNA contains a potential ORF of 867 bp 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 the expression of this novel gene is high in testis and in the human leukemic T cell line Jurkat and lower in other tissues including all fetal tissues studied. We have called to this novel gene c21-LRP (chromosome 21 leucine-rich protein) and, because of its location in the DS-2 region, it could be a candidate for some of the DS anomalies. Mapping experiments have narrowed the location of the c21-LRP gene between markers D21S343 and D21S268 from chromosome 21. Analysis of the c21-LRP protein predicts two transmembrane helices and detects several signatures and potential homologies to known proteins pointing toward several potential roles for this protein.