Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.5.1.3 (dihydrofolate reductase)
 5,819 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The chromosomal location of the human dihydrofolate reductase (DHFR; EC 1.5.1.3) gene that is amplified in a methotrexate-resistant human cell line has been investigated by screening a number of human-Chinese hamster ovary cell hybrids containing terminal and interstitial deletions in human chromosome 5. A correlation of genomic blotting data with the chromosome 5 constitution of the individual hybrids has allowed the assignment of the human DHFR gene to 5q23. The present work also establishes the location of the related intronless pseudogene psi HD1 in chromosome 3.
 ...
PMID:Assignment of human dihydrofolate reductase gene to band q23 of chromosome 5 and of related pseudogene psi HD1 to chromosome 3. 385 32

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 (psi HD1) 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 X 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 psi HD1 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.
 ...
PMID:A human dihydrofolate reductase pseudogene and its relationship to the multiple forms of specific messenger RNA. 630 53