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A human dihydrofolate reductase pseudogene and its relationship to the multiple forms of specific messenger RNA

Masters, Jeffrey N. and Yang, Jiyoung K. and Cellini, Alessandra and Attardi, Giuseppe (1983) A human dihydrofolate reductase pseudogene and its relationship to the multiple forms of specific messenger RNA. Journal of Molecular Biology, 167 (1). pp. 23-36. ISSN 0022-2836. doi:10.1016/s0022-2836(83)80032-1.

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The presence of dihydrofolate reductase (DHFRase)-specific sequences that, in contrast to the normal DHFRase gene, are not amplified in a methotrexate-resistant cell line, has been detected in the DNA from human sperm and from several human cell lines. DNA fragments containing some of these sequences have been isolated from a cosmid library of human sperm DNA. One of these fragments contains a DHFRase pseudogene (λHD1) that completely lacks introns, has 92% sequence homology to the corresponding region of normal DHFRase complementary DNA, but exhibits several alterations that make it nonfunctional. The sequence analysis of the inserts of four different plasmids containing the reading frame and varying lengths of the 3′ non-coding regions of human DHFRase-specific cDNAs has revealed that the 3′ non-coding segments all are colinear in their corresponding portions. Furthermore, the data indicate that the cDNA of one of the plasmids is probably derived from the smallest of the three main human DHFRase messenger RNAs, the 0·8×10^3 base (0·8 kb) mRNA, the cDNA of two others, from the 1·0 kb mRNA, and the cDNA of the fourth, from a longer mRNA. These results are consistent with the idea that the multiple forms of DHFRase mRNA in human cells derive from the same gene by different transcription or RNA-processing events. Moreover, the sequence comparison between the ψHD1 and the different DHFRase cDNAs clearly indicates that, if an mRNA intermediate has participated in the formation of this pseudogene, a form of mRNA larger than the 1·0 kb mRNA, probably the 3·8 kb mRNA, must have been involved.

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Additional Information:© 1983 Published by Elsevier. Received 15 December 1982. These investigations were supported by National Institutes of Health grants GM11726 and T32 GM07616. We are very grateful to A. Chomyn for helpful discussions and to J. Ellison for a gift of human sperm DNA and to J. Ellison and L. Hoo(l for providing us with the human DNA cosmid library.
Funding AgencyGrant Number
NIH Predoctoral FellowshipT32 GM07616
Issue or Number:1
Record Number:CaltechAUTHORS:20190501-163158550
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Official Citation:Jeffrey N. Masters, Jiyoung K. Yang, Alessandra Cellini, Giuseppe Attardi, A human dihydrofolate reductase pseudogene and its relationship to the multiple forms of specific messenger RNA, Journal of Molecular Biology, Volume 167, Issue 1, 1983, Pages 23-36, ISSN 0022-2836, (
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:95159
Deposited By: George Porter
Deposited On:02 May 2019 15:33
Last Modified:16 Nov 2021 17:10

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