A novel splice variant of folate receptor 4 predominantly expressed in regulatory T cells.
BACKGROUND
Regulatory T cells (Tregs) are required for proper maintenance of immunological self-tolerance and immune homeostasis. Folate receptor 4 (FR4) is expressed at high levels in transforming growth factor-beta (TGF-β)-induced Tregs and natural Tregs. Moreover, antibody-mediated targeting of FR4 is sufficient to mediate Treg depletion.


RESULTS
In this study, we describe a novel FR4 transcript variant, FR4D3, in which exon 3 is deleted. The mRNA of FR4D3 encodes a FR4 variant truncated by 189 bp. FR4D3 was found to be predominantly expressed in CD4(+)CD25(+) Treg cells. Overexpression of FR4D3 in CD4(+)CD25(+) Treg cells in vitro stimulated proliferation, which may modulate the ability of these cells to bind and incorporate folic acid.


CONCLUSIONS
Our results suggested that high levels of FR4D3 may be critical to support the substantial proliferative capacity of Treg cells.
Institute of Immunology, PLA, Third Military Medical University, Chongqing, Peoples Republic China.
Yi
Y
Tian
Guoqiang
G
Wu
Jun-Chao
JC
Xing
Jun
J
Tang
Yi
Y
Zhang
Ze-Min
ZM
Huang
Zheng-Cai
ZC
Jia
Ren
R
Zhao
Zhi-Qiang
ZQ
Tian
Shu-Feng
SF
Wang
Xiao-Ling
XL
Chen
Li
L
Wang
Yu-Zhang
YZ
Wu
Bing
B
Ni
D017398:Alternative Splicing; D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D049109:Cell Proliferation; D005260:Female; D005434:Flow Cytometry; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D017423:Sequence Analysis, RNA; D050378:T-Lymphocytes, Regulatory / Q000378:metabolism* / Q000502:physiology
D020033:Protein Isoforms; D011956:Receptors, Cell Surface; C543634:folate receptor 4, mouse