Cloning, expression pattern and mapping to Xq of NAP1L3, a gene encoding a peptide homologous to human and yeast nucleosome assembly proteins

From a human fetal brain cDNA library, we isolated a never gene sharing significant homology with the genes of nucleosome assembly proteins (NAPs). This cDNA clone, designated NAP1L3 (nucleosome assembly protein 1-like 3), contained an open reading frame of 15 18 nucleotides encoding 506 amino acids. Its predicted amino acid sequence showed 46 % identity and 65 % similarity with NAP 1L. In its C-terminal half NAP 1L3 contained several characteristic motifs strict-conserved with NAP 1L and yeast NAP1, but the N-terminal half showed little conservation. Northern-blot analysis revealed strong expression of a 3.0-kb transcript in human adult brain and weak expression in heart. NAP1L3 was closely linked to a marker (DXS990) mapped to chromosome bands Xq21.3-->q22, where genes responsible for several X-linked mental retardation syndromes have been localized.