THE IDENTIFICATION AND EXPRESSION OF HEME OXYGENASE-2 ALTERNATIVE TRANSCRIPTS IN THE MOUSE

Murine heme oxygenase-2 (HO-2) cDNA sequences were determined through the assembly of mouse expressed sequence tag (EST) sequences using the rat NO-2 sequence as a template. The sequence analysis revealed two m RNA isoforms, probably arising through alternative splicing, which dif fered in their 5'-untranslated region (UTR), and were named HO-2a and HO-2b. One EST sequence included an extended 3'-UTR and suggested ther e may be a choice of poly-adenylation (poly-A) signal sequence. Revers e transcriptase polymerase chain reaction (PCR) suggested that HO-2a m RNA may be specifically expressed in the testis, while HO-2b mRNA was present in all tissues analysed. Furthermore, HO-2a and HO-2b transcri pts were both found to include the extended 3'-UTR, but these transcri pts were detected only in the testis. Northern analysis of a greater r ange of tissues confirmed the testis-specific expression of HO-2a mRNA and suggested that the transcripts which included the extended 3'-UTR were a small minority of the NO-2 mRNA population. These alternative murine HO-2 transcripts suggest that mechanisms such as mRNA transport , translational efficiency or mRNA turnover may be implicated in the r egulation of HO-2 gene expression, most notably in the testis. (C) 199 8 Elsevier Science B.V. All rights reserved.