T cell receptor gamma and delta gene junctional sequences in SCID mice: excessive P nucleotide insertion.
T cell receptor gamma and delta gene junctional sequences in SCID mice: excessive P nucleotide insertion.
复制标题
SCID 小鼠中 T 细胞受体 γ 和 δ 基因连接序列：过多的 P 核苷酸插入。
DOI：
10.1084/jem.174.4.769
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发表时间：
1991
期刊：
影响因子：
--
通讯作者：
Tucker,PW
中科院分区：
文献类型：
--
作者：
Kienker,LJ;Kuziel,WA;Tucker,PW
The severe combined immunodeficiency (SCID) mutation has been postulated to affect a V (D) J recombinase activity involved in coding joint formation. Analysis of 38 joints from 34 distinct sequences of normally rearranged T cell receptor (TCR) 3'and~ genes from adult, SCID thymocytes reveals coding joints with an increased number of P nucleotides. One-third of P sequences are>--4 nucleotides in length and P elements of up to 15 bases are observed. This suggests that the SCID defect deregulates P nucleotide addition. Consequently, essential V (D) J recombination intermediates may seldom be generated. y oung adult mice homozygous for the SCID mutation are severely deficient in mature B and T cells (1). Observation of abnormal antigen-receptor gene rearrangements in vitally transformed SCID bone marrow cells and spontaneous SCID thymic lymphocytes suggested initially that this might be due to defective V (D) J recombinase activity in these mice (2). Sequence analysis of numerous abnormal SCID Ig (3-7) and TCR (8) rearrangements, as well as studies with recombination substrates (9-11) have subsequently shown that CB-17 scid/scid mice contain a V (D) J recombinase that recognizes recombination signal sequences adjacent to variable region gene segments (V, D, and J), cleaves the DNA normally at the borders of the variable region gene segments, ligates the signal sequences at a normal frequency, but fails to recombine the V, D, and J gene segments at any frequency comparable to that in normal cells. Further, V (D) Jjoints frequently result in deletion of one or both of the participating coding elements (2-7).Recently, while studying natural killer cells and T cell progenitors in the thymus of SCID mice, we obtained evidence for full-length, potentially productive, TCK 3" chain transcripts (12). Southern blot analyses revealed normal rearrangements at the TCK 3" locus and PCK amplification, cloning and DNA sequencing were performed to capture TCR% and partner chain,/~, gene junctional sequences with small deletions in the coding segments. Nucleotide sequences reveal that many characteristics of SCID V (D) J recombination are indistinguishable from normal V (D) J recombination (Kienker, LJ, WA Kuziel, BA Garni-Wagner, V. Kumar, and PW Tucker, manuscript submitted for publication), but P nucleotide addition is different. P nucleotides are newly distinguished inserted bases at coding joints that form inverted repeats of the neighboring gene segment termini (13). Presumably, there are up to 2 P nucleotides at the ends of
