Wide distribution of the MICA-MICB null haplotype in East Asians.
Stress-inducible MICA (MHC class I chain-related A) is known to bind to NKG2D, which is one of the natural killer (NK) cell receptors, and plays a role in immune surveillance. We have reported that a MICA-MICB null haplotype is in linkage disequilibrium with HLA-B*4801 in the Japanese population. In the haplotype, an approximately 100-kb deletion, including the entire MICA gene, was observed and MICB possessed a premature stop codon. In this study, a multiplex polymerase chain reaction (PCR) method was developed for detecting the MICA deletion. MICB alleles were typed by PCR-single-strand conformation polymorphism (SSCP) method and direct sequencing. The frequency of the MICA-MICB null haplotype was 3.7% on the average, and was strongly associated with HLA-B48 in seven East Asian populations. It was presumed that the stop codon of MICB gene generated after the large-scale deletion. The wide distribution of the null haplotype at polymorphic frequencies suggests that the haplotype has been conservatively maintained because of some selective advantage.
Komatsu-Wakui
M
M
Department of Human Genetics, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
Tokunaga
K
K
Ishikawa
Y
Y
Leelayuwat
C
C
Kashiwase
K
K
Tanaka
H
H
Moriyama
S
S
Nakajima
F
F
Park
M H
MH
Jia
G J
GJ
Chimge
N O
NO
Sideltseva
E W
EW
Juji
T
T
D000483:Alleles; D044466:Asian People / Q000235:genetics; D005202:Asia, Eastern; D017353:Gene Deletion; D005787:Gene Frequency; D005805:Genes, MHC Class I; D015235:HLA-B Antigens / Q000235:genetics; D006239:Haplotypes / Q000235:genetics*; D015395:Histocompatibility Antigens Class I / Q000235:genetics*; D006650:Histocompatibility Testing; D006801:Humans; D016133:Polymerase Chain Reaction; D018807:Polymorphism, Single-Stranded Conformational
D015235:HLA-B Antigens; D015395:Histocompatibility Antigens Class I; C099187:MHC class I-related chain A; C098080:MICB antigen