Glutathione Sulfur Transferase Region of Human Chromsome 1

  • GTM12 = AC000032
  • GTM11 = AC000037
  • GTM1 = AC000031

    Sequence of Three Cosmids, cGTM1, cGTM11 and cGTM12 from Human Chromosome 1

    Yingping Wang, Dennis Burian, Shi-jie Xu, William R. Pearson and Bruce A. Roe

    Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK 73019 and Department of Biochemistry, University of Virginia, Charlottesville, VA 22908

  • We have sequenced two cosmids, cGTM1 and cGTM12, from human chromosome 1. Our strategy involved random shotgun cloning of nebulized cosmid DNA, isolation of the subclones and sequencing of the subclones with dye-terminator chemistry. Cosmid sequence was assembled using both the Staden package and Phrap.
  • The sequence of cGTM1 has been assembled into one contig of 39 Kb. We have mapped the location of two of the GSTM genes, GSTM2 and GSTM4, to this cosmid. In addition, we have found a region of GSTM gene homology in the 3' region of this cosmid which differs from any of the know GSTM genes.
  • As an indicator of the instability of this region, cGTM12 recombined while preparing cosmid DNA for sequencing, originally resulting in the incorrect assembly of this cosmid into a single 17Kb contig. This lead us to examine the structure of cGTM12 by restriction digest of different preparations of the cosmid from individual colonies. Close analysis lead us to believe that the size of the cosmid DNA obtained from individual colonies varied, and restriction enzyme digests confirmed this observation. We discovered that an approximately 7 Kb deletion had occurred in the original preparation of this cosmid. The sequence of a cosmid containing both the original 17Kb and the 7Kb deletion now is complete and analysis of this 24Kb insert reveals the presence of all eight exons of the GSTM1 gene and four exons from GSTM5 in cGTM12.
  • Since it has been shown that GSTM1 is deleted in approximately one half the human poplulation. It is interesting to note that the region of cGTM12 which was lost in our initial cosmid corresponds to the the naturally occurring deleted region in humans. Therefore, we expect that the recombination "hotspots" that are present in humans and located in these cosmids, also may be naturally deleted when grown in bacteria. Thus, having the sequence of this region available may assist in furthering our understanding of recombinogenic sites and the mechanisms surrounding genetic instability.
  • We acknowledge support from NIH-NCHGR, NIH-AG, Am. Cancer Soc. and NSF-EPSCoR.
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    Bruce Roe, broe@ou.edu