Down syndrome critical region gene 2: Expression during mouse development and in human cell lines indicates a function related to cell proliferation

The isolation of the genes located in chromosome 21 and the characterisatio n of their function are essen tial steps towards the understanding of the p hysiopathological mechanisms involved in Down syndrome. We have used two co mplementary approaches to characterise the function of the novel gene DSCR2 (Down Syndrome Critical Region gene 2): the isolation and characterisation of the mouse gene homologue to the human DSCR2 gene, and the analysis of t he expression of the gene in different human cell lines, We have isolated a nd characterised a 1012 bp of a mouse cDNA having a high homology to the hu man DSCR2 gene. The predicted mouse dscr2 protein has an identity of 85.4% as compared to the human protein, indicating that the DSCR2 protein has bee n conserved during the evolution. However, the amino acid sequence is not h omologous to other known proteins, or to the known protein domains. The dsc r2 gene is expressed throughout all the stages of the mouse embryo developm ent. In the adult mouse the gene is expressed in testis, kidney, liver, bra in, heart, skeletal muscle, and pancreas. The expression analysis of the DS CR2 gene in different human tumour derived cell lines indicates that the ge ne is expressed in all proliferating cell lines tested. The levels of the D SCR2 mRNA correlate with cellular growth of T98G and Jurkat cells in respon se to different treatments. The expression pattern throughout the foetal de velopment together with the correlation observed with the cell cycle indica tes a possible function for the DSCR2 gene related to cell proliferation. ( C) 2000 Academic Press.