Comparison of mouse and human NASP genes and expression in human transformed and tumor cell lines

We previously cloned and sequenced cDNAs encoding mouse NASP (mNASP), a cel l cycle regulated histone HI binding protein. Here we report the genomic se quence and organization for mNASP along with its 5' regulatory region and c ompare these with human NASP (hNASP). The mNASP gene contains 16 exons inte rrupted by 15 introns. The sequence encoding testis mNASP uses all 16 exons while the somatic form uses 13 exons by differential splicing. All the exo ns conform to the AG/GT splicing rule. Putative TATA box-containing transcr iption initiation sites are present for somatic NASP in human and mouse and for testis hNASP. Comparison of the promoter regions of mNASP and hNASP ap proximately 1 kb upstream of the transcription start sites for the two spli ce variants revealed a number of possible transcription factor binding site s relevant to specific patterns of NASP tissue expression. The presence of single bands on Southern blots of mouse genomic DNA suggests that mNASP is a single copy gene although pseudogenes exist in both the mouse and human g enomes. Chromosome fluorescence by in situ hybridization revealed that mNAS P is present on chromosome 4, in an area that corresponds to band 4D1, a re gion syntenic to the locus of hNASP on chromosome 1. Additionally, we repor t that human somatic and testis NASP mRNAs are expressed at varying levels in all the transformed cell lines and human tumors tested, further supporti ng NASP's role in the cell cycle of dividing cells. (C) 2001 Published by E lsevier Science B.V.