A geological interpretation of the deep seismic reflection line CROP 3 (Italian program CROsta Profonda: deep crust, profile no. 3), which crosscuts the Northern Apennines from the Tyhrrenian to the Adriatic coast, is presented. The profile images the lithosphere up to 15 s TWT and highlights several peculiarities: (a) the lower crust is bedded by discontinuous sub parallel reflective markers which terminate at ≈ 7 s beneath the western side of the profile; (b) in the same area a notable reflection is recognizable at 10 s and is interpreted as the top of the asthenosphere; (c) east‐plunging shear zones are recognizable throughout the crust. By contrast, the Adriatic (outer) side of this line shows: (a) reflections deepening westward, from 13 to 15 s TWT, related to the base of the crust (33–38 km depth); (b) the absence of thick bedding of reflective markers within the lower crust; and (c) tectonic structures affecting the basement which are different from those which deform the cover of the Northern Apennines. Geological interpretation is based on the eastward migration of ductile shear zones which have been recognized on the seismic line. The bending of the outer zone crust is considered to be a consequence of the rifting process with the application of pushing forces against the Adriatic lithosphere which cannot escape toward east.
For nearly a decade since the mapping of the multiple endocrine neoplasia type 1 (MEN1) locus to 11q13 and the suggestion that it is a tumour suppressor gene, efforts have been made to identify the gene responsible for this familial cancer syndrome. Recently, we have identified the MEN1 gene by the positional cloning approach. This effort involved construction of a 2.8-Mb physical map (D11S480-D11S913) based primarily on a bacterial clone contig. Using these resources, 20 new polymorphic markers were isolated which helped to reduce the interval for candidate genes by haplotype analysis in families and by loss of heterozygosity (LOH) studies in approximately 200 tumours, utilizing laser-assisted microdissection to obtain tumour cells with minimal or no admixture by normal cells. The interval was narrowed by LOH to only 300 kb, and nearly 20 new transcripts that map to this region of 11q13 were isolated and characterized. One of the transcripts was found by dideoxyfingerprinting and cycle sequencing to harbour deleterious germline mutations in affected individuals from MEN-1 kindreds and therefore identified as the MEN1 gene. The type of germline mutations and the identification of mutations in sporadic tumours support the Knudson's two-hit model of tumorigenesis for MEN-1. Efforts are being made to identify the function of the MEN1 gene-encoded protein, menin, and to study its role in tumorigenesis.
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