B. Nadel et Aj. Feeney, NUCLEOTIDE DELETION AND P-ADDITION IN V(D)J RECOMBINATION - A DETERMINANT ROLE OF THE CODING-END SEQUENCE, Molecular and cellular biology, 17(7), 1997, pp. 3768-3778
During V(D)J recombination, the coding ends to be joined are extensive
ly modified. Those modifications, termed coding-end processing, consis
t of removal and addition of various numbers of nucleotides, We previo
usly showed in vivo that coding-end processing is specific far each co
ding end, suggesting that specific motifs in a coding-end sequence inf
luence nucleotide deletion and P-region formation. Ln this study, me c
reated a panel of recombination substrates containing actual immunoglo
bulin and T-cell receptor coding-end sequences and dissected the role
of each motif hv comparing its processing pattern with those of varian
ts containing minimal nucleotide changes from the original sequence. O
ur results demonstrate the determinant role of specific sequence motif
s on coding-end processing and also the importance of the contort in w
hich they are found. We show that minimal nucleotide changes in keg po
sitions of a coding-end sequence can result in dramatic changes in the
processing pattern. We propose that each coding-end sequence dictates
a unique hairpin structure, the result of a particular energy conform
ation between nucleotides organizing the loop and the stem, and that t
he interplay between this structure and specific sequence motifs influ
ences the frequency and location of nicks which open the coding-end ha
irpin, These findings indicate that the sequences of the coding ends d
etermine their own processing and have a profound impact on the develo
pment of the primary B- and T-cell repertoires.