Transcriptional analysis of the 69-kb sequence centromeric to HLA-J: A dense and complex structure of five genes

Performed within the framework of the sequencing of the 356-kb MHC class I distal region, systematic bioinformatic annotation and preliminary experime nts conducted on the whole sequence indicate a high level and a complex pat tern of expression. In this paper, we analyze a particular stretch of 69 kb centromeric to the HLA-J gene, in which we identify 21 different mRNAs mai nly expressed in testis, and characterize five different transcription unit s, HZFw, HZFc, HCGV, HTEX6, and HTEX4. These tightly linked genes form a cl uster conserved between human and mouse and displaying a high gene density of about one every 14 kb. Alternative splicing processes are observed for a ll the genes, together with an alternative polyadenylation event for gene H TEX4, sense/antisense mRNA overlaps for HZFw and HZFc, for HZFw and HCGV at their 3' end, and for HTEX6 and HTEX4 at their 5' end. This complex genomi c structure suggests a mechanism of coregulation by cia-interaction in gene expression.