Browsing by Author "Lawson, T N"

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    Physical mapping of an early sea urchin gene battery from Parenchinus angulosus
    (1988) Lawson, T N; Sewell, Bryan Trevor; Von Holt, Claus
    The aim of this project was to characterise an early histone gene battery isolated from Parenchinus angulosus. An early histone gene battery (named H27) which was believed to have been isolated from Parenchinus angulosus, appeared by restriction enzyme mapping and partial sequencing to be identical to H22, an early histone gene battery isolated from Psammechinus miliaris. (This latter gene was obtained from M. Birnstiel.) This was further confirmed by electron microscopy, and proved to be a convenient testing ground for the electron microscopic techniques of denaturation mapping and heteroduplex anlysis. Another gene battery (named SU1) isolated fromParenchinus angulosus, was then characterised using the techniques developed whilst studying H27. The restriction enzyme map of this clone is different to that of H22, indicating that differences do indeed exist between these two early histone gene batteries. SU1 also showed the expected order of the five histone genes, as determined by hybridization against the coding regions of H22. The denaturation map of SU1 showed AT rich spacer regions and GC rich coding regions. Heteroduplex analysis indicated that the spacer regions between the Hl and H2A, the H2A and H3, and the H3 and the H2B gene coding areas are essentially nonhomologous. The H4 structural gene and corresponding spacer regions were not included in this analysis. Because it is known that all the five histones are coded for on the same strand of DNA in H22, and that each of the genes is transcribed in the same direction, it follows that, the same holds for, at least, the Hl, H2A, H3 and H2B genes of SU1.