GENERATION OF A TRANSCRIPTION MAP OF A 1 MBASE REGION CONTAINING THE HFE GENE (6P22)

A transcription map was generated of a 1 Mb interval including the HFE gene on 6p22. Thirty-seven unique cDNA fragments were characterised f ollowing their retrieval from hybridisation of immobilised YACs to pri mary pools of cDNAs prepared from RNA of foetal brain, human liver, fo etal human liver, placenta, and CaCo2, cell line. All cDNA fragments w ere positioned on the physical map on the basis of presence in aligned and overlapping YACs and cosmid clones of the region. The isolated cD NAs together with established or published sequence tagged sites (STSs ) and markers provided sufficient landmark density to cover approximat ely 90% of the 1 Mb interval with cosmid clones. The precise localisat ion of two known genes (NPT1 and RING finger protein) was established. A minimum of 14 additional transcription units has also been integrat ed. Twenty-eight cDNA fragments showed no similarity with known sequen ces, but 20 of these detected discrete mRNAs upon northern analysis. T heir characterisation is still under investigation. Eleven new polymor phisms were also identified and localised, and the HFE genomic structu re was better defined. This integrated transcription map considerably extends a recently published map of the HFE region. It will be useful for the identification of genetic defects mapping to this region and f or providing template resources for genomic sequencing.