Structure, organization, and somatic rearrangement of T cell gamma genes

Predominant variable region gene usage by gamma/delta T cell receptor-bearing cells in the adult thymus.

“…The following information is helpful in analysis of the blot hybridization data: (a) Donor B6 thymocyte-derived Vy2-CylCyl rearrangements can be distinguished from the BW5147-derived Vy2JylCyl rearrangement due to a polymorphism between AKR (strain of origin BW5147) and B6 in an Eco RI site located 3' of the Cyl gene ; the B6-and AKR-derived rearranged Vy2JylCyl genes reside on 17 and 19 kb Eco RI fragments, respectively (B). In DN1 .l, the rearrangement of Vyl .3 to Jy4Cy4 yields a 6 .6 kb Eco RI fragment and a 3 .5 kb Hind III fragment (E and G), consistent with the location of germline Eco RI sites (9) . For comparison, rearrangement of Vyl .l to Jy4 yields a 9 .5 kb Eco RI fragment (see above) ; based on the location of Eco RI sites in germline DNA, rearrangement of Vy1 .2 to Jy4 would yield an 11 .6 kb Eco RI fragment .…”

“…Earlier studies have shown that the potential diversity of the y chain in the mouse is relatively limited, with only seven (known) V gene segments, three functional J segments, and no known D segments (9-13) . While there is clear evidence ofjunctional diversity created at VyJY joints, presumably due in part to the addition of random nucleotides (N regions), the extent of N diversity in y chains may be relatively limited (9)(10)(11)(12) . Moreover, y gene use in the adult thymic population of y/S cells is strikingly nonrandom, with most cells expressing the product of a single rearranged gene, Vy2Jy1Cy1 (34a, 34b) .…”

“…4 A) (9)(10)(11)(12)(13) . Therefore, the potential V-region diversity of the y chain is limited compared with that of the immunoglobulin heavy or light chains, and the a and ß subunits of the a/ß TCR .…”

T cell receptor gamma/delta chain diversity.

“…Earlier studies (2,6,12,13) have indicated that all these hybridomas express glycosylated y chains that are not derived from Vy-Cy4 transcripts since the antiserum used to detect these y chains does not react with Cy4 chains (nomenclature according to Garman et al, [10]). Furthermore, since the Cy3 locus is a pseudogene (8) and, at least for the C57BL/6 mice, V71 .2-C"y2 transcripts would result in nonglycosylated y chains (19), these hybridomas most likely express y chains derived from Vy-CyI transcripts.…”

“…The y chain gene family is known to encode four C regions (1 pseudogene) and seven V regions which can give rise to at least five y chain mRNA transcripts (8)(9)(10)(11)(12)(13) . It is unknown if all these transcripts give rise to cell surface-expressed proteins.…”