Lohwasser S, Hande P, Mager D L, Takei F
Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, Canada.
Eur J Immunol. 1999 Mar;29(3):755-61. doi: 10.1002/(SICI)1521-4141(199903)29:03<755::AID-IMMU755>3.0.CO;2-X.
Multiple NK cell receptors for MHC class I have been identified. They include killer inhibitory receptors and CD94/NKG2 heterodimers in humans and the Ly49 family in mice. Here we report the cloning of murine NKG2A, B and C. The deduced amino acid sequence of mouse NKG2A contains only one consensus cytoplasmic immunoreceptor tyrosine-based inhibitory motif (ITIM). NKG2A from B6 and BALB/c mice differ by six amino acid residues in the extracellular domain. Murine NKG2B, like its human conterpart, appears to be a splice variant of NKG2A and lacks a large portion of the stalk region. Murine NKG2C lacks an ITIM in its cytoplasmic domain, a feature shared by human and rat NKG2C. However, unlike the human counterpart, the transmembrane domain of mouse NKG2C does not contain a charged amino acid residue. Mouse NKG2A mRNA was detected in IL-2-activated NK cells and spleen cells but not in other tissues. The NKG2A gene was localized on the distal portion of chromosome 6 where the NK complex has been located. These results further extend the repertoire of C-type lectin receptors on murine NK cells.
已鉴定出多种针对MHC I类分子的自然杀伤（NK）细胞受体。在人类中，它们包括杀伤抑制受体和CD94/NKG2异二聚体，在小鼠中则为Ly49家族。在此，我们报告了小鼠NKG2A、B和C的克隆。小鼠NKG2A推导的氨基酸序列仅含有一个基于免疫受体酪氨酸的保守抑制基序（ITIM）。来自B6和BALB/c小鼠的NKG2A在胞外结构域有六个氨基酸残基的差异。小鼠NKG2B与其人类对应物一样，似乎是NKG2A的剪接变体，并且缺少大部分柄部区域。小鼠NKG2C在其胞质结构域缺乏ITIM，这是人类和大鼠NKG2C共有的特征。然而，与人类对应物不同的是，小鼠NKG2C的跨膜结构域不包含带电荷的氨基酸残基。在白细胞介素-2激活的NK细胞和脾细胞中检测到小鼠NKG2A mRNA，但在其他组织中未检测到。NKG2A基因定位于6号染色体远端，即NK复合体所在的位置。这些结果进一步扩展了小鼠NK细胞上C型凝集素受体的种类。
