Differential usage of delta recombining element and V delta genes during
T-cell ontogeny
J Hara, Y Takihara, K Yumura-Yagi, S Ishihara, A Tawa, TW Mak, EW Gelfand, S Okada and K Kawa-Ha
Department of Pediatrics, Osaka University Hospital, Japan.
We analyzed the usage of the delta recombining element (delta Rec) and six
V delta genes in cell samples from 15 patients with CD3- and 10 patients
with CD3+ T-cell acute lymphoblastic leukemia in an attempt to define the
hierarchy of genetic events that is associated with the T- cell receptor
(TCR) alpha/delta gene complex during T-cell ontogeny. Based on the
deletion patterns of these genes, we surmised their relative order on
chromosome 14 to be as follows: 5'-V delta 4, V delta 6, V delta 1, V delta
5, delta Rec, V delta 2, D delta 1-3, J delta 1- 3, C delta, V delta 3-3'.
In agreement with previous reports, V delta 1 was found to be
preferentially rearranged in CD3+ samples. In CD3- samples, V delta 2 and V
delta 3 rearrangements were observed at a high frequency. Incomplete V
delta D delta rearrangements using V delta 2 or V delta 3, which are
closest to C delta, were observed in three patients with CD3- and one
patient with CD3+. These results suggest that V delta 2- and V delta
3-(Dn)D delta 3 recombinations are among the earliest recombinational
events. Delta Rec was observed to be rearranged to phi J alpha on one
allele. In addition, delta Rec rearrangements to J delta 1 and J alpha
close to phi J alpha were also demonstrated on three alleles and one
allele, respectively. Delta Rec rearrangements to J delta and J alpha other
than phi J alpha also inhibit expression of the TCR delta locus.
Approximately half of the alleles with J delta rearrangements showed no
involvement of known V delta or delta Rec, indicating the existence of
other, yet- uncharacterized V delta or delta Rec-like segments.
Volume 78,
Issue 8,
pp. 2075-2081,
10/15/1991
Copyright © 1991 by The American Society of Hematology
