PMID- 9689927
OWN - NLM
STAT- MEDLINE
DCOM- 19980814
LR  - 20190816
IS  - 0165-4608 (Print)
IS  - 0165-4608 (Linking)
VI  - 105
IP  - 1
DP  - 1998 Aug
TI  - Chromosomal localization of the murine RFC-1 gene encoding a folate transporter 
      and its amplification in an antifolate resistant variant overproducing the 
      transporter.
PG  - 29-38
AB  - A variant of the L1210 cell (L1210/R83) selected in the presence of the 
      lipophilic antifolate, metoprine, and a concentration of the natural 
      diastereoisomer of 5-formyltetrahydrofolate, lL5CHO-folateH4, suboptimum for 
      growth exhibited a 35-fold increase compared to parental L1210 cells in 
      one-carbon, reduced folate transport. This was evidenced by the increase in Vmax 
      for [3H]MTX (methotrexate) influx and a commensurate increase in the amount of 
      the 46 kilodalton (kDa) transport protein and reduced folate carrier (RFC-1) 
      mRNA. The variant is resistant to lipophilic antifolates, but shows collateral 
      sensitivity to classical folate analogues. Karyotype analysis of L1210/R83 cells 
      revealed the presence of several new chromosome abnormalities. One of these was a 
      large, submetacentric marker chromosome comprising a normal #10 and a longer, 
      abnormally banded arm of uncertain origin which exhibited an interstitial, palely 
      staining, HSR-like segment. The results of Southern and Northern blotting showed 
      that the RFC-1 gene copy number and RNA transcript level were markedly increased 
      (30-35 fold) in L1210/R83 cells. Fluorescence in situ hybridization (FISH) 
      analysis revealed that the HSR-like segment in these cells was the site of 
      amplified RFC-1 genes. Independent revertant subclones, obtained following growth 
      in the absence of selection pressure, showed four- to 12-fold decreases in 
      [3H]MTX influx Vmax and in amount of NHS (N-hydroxysuccinimide)-[3H]MTX affinity 
      labeled one-carbon, reduced folate transporter compared to L1210/R83 cells. RFC-1 
      gene copy number also decreased, and the mean length of the HSR in these 
      revertants declined 1.6- to 5-fold. Based upon genomic nucleotide sequencing, the 
      RFC-1 gene in the normal mouse genome was localized to chromosome 10 in close 
      association with the alpha 1 (Col18a1) collagen gene at 10B3(locus 41cM). The 
      close association of these genes was confirmed by other data showing that the 
      alpha 1 collagen gene was co-amplified in L1210/R83 cells. These results document 
      the amplification at the site of a putative HSR in an L1210 cell variant of the 
      RFC-1 gene regulating expression of the one-carbon, reduced folate transporter.
FAU - Roy, K
AU  - Roy K
AD  - Program in Cell Biology and Genetics, Graduate School of Medical Sciences, 
      Cornell University, New York, New York, USA.
FAU - Chiao, J H
AU  - Chiao JH
FAU - Spengler, B A
AU  - Spengler BA
FAU - Tolner, B
AU  - Tolner B
FAU - Yang, C H
AU  - Yang CH
FAU - Biedler, J L
AU  - Biedler JL
FAU - Sirotnak, F M
AU  - Sirotnak FM
LA  - eng
GR  - CA08748/CA/NCI NIH HHS/United States
GR  - CA56517/CA/NCI NIH HHS/United States
PT  - Journal Article
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - Cancer Genet Cytogenet
JT  - Cancer genetics and cytogenetics
JID - 7909240
RN  - 0 (Carrier Proteins)
RN  - 0 (Folic Acid Antagonists)
RN  - 0 (Membrane Proteins)
RN  - 0 (Membrane Transport Proteins)
RN  - 0 (RNA, Messenger)
RN  - 0 (SLC19A2 protein, human)
RN  - 0 (Slc19a2 protein, mouse)
RN  - EC 1.5.1.3 (Tetrahydrofolate Dehydrogenase)
SB  - IM
MH  - Animals
MH  - Carrier Proteins/antagonists & inhibitors/biosynthesis/*genetics
MH  - Chromosome Aberrations/genetics
MH  - Chromosome Disorders
MH  - Chromosome Mapping
MH  - Chromosomes, Human, Pair 10/*genetics
MH  - *Drug Resistance, Neoplasm
MH  - Folic Acid Antagonists/*pharmacology
MH  - *Gene Amplification
MH  - Gene Dosage
MH  - Humans
MH  - Karyotyping
MH  - Leukemia L1210/genetics/metabolism
MH  - Membrane Proteins/antagonists & inhibitors/biosynthesis/*genetics
MH  - *Membrane Transport Proteins
MH  - Mice
MH  - RNA, Messenger/analysis
MH  - Tetrahydrofolate Dehydrogenase/genetics
MH  - Tumor Cells, Cultured
EDAT- 1998/08/05 00:00
MHDA- 1998/08/05 00:01
CRDT- 1998/08/05 00:00
PHST- 1998/08/05 00:00 [pubmed]
PHST- 1998/08/05 00:01 [medline]
PHST- 1998/08/05 00:00 [entrez]
AID - S0165460898000053 [pii]
AID - 10.1016/s0165-4608(98)00005-3 [doi]
PST - ppublish
SO  - Cancer Genet Cytogenet. 1998 Aug;105(1):29-38. doi: 
      10.1016/s0165-4608(98)00005-3.