RT Journal Article
SR Electronic
T1 Analysis of human immunoglobulin VDJ and DJ rearrangements shows N region synthesis by concatenation of cytosine-rich strands preferentially originating from trimmed germline gene segments
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 248021
DO 10.1101/248021
A1 Tina Funck
A1 Mike Bogetofte Barnkob
A1 Nanna Holm
A1 Line Ohm-Laursen
A1 Camilla Slot Mehlum
A1 Sören Möller
A1 Torben Barington
YR 2018
UL http://biorxiv.org/content/early/2018/01/23/248021.abstract
AB The formation of non-templated (N) regions during immunoglobulin gene rearrangement is a major contributor to antibody diversity. To gain insights into the mechanisms behind this, we studied the nucleotide composition of N regions within 29,962 unique human VHDJH-rearrangements and 8,728 unique human DJH-rearrangements containing exactly one identifiable D-gene segment and thus two N regions, N1 and N2. We found a distinct decreasing content of cytosine (C) and increasing content of guanine (G) across each N region, suggesting that N regions are typically generated by concatenation of two 3’-overhangs synthesized by addition of nucleoside triphosphates with a preference for dCTP. This challenges the general assumption that the terminal deoxynucleotidyl transferase favors dGTP in vivo. Furthermore, we found that the G and C gradients depended strongly on whether the germline gene segments were trimmed or not. Our data show that C-enriched N addition preferentially happens at trimmed 3’-ends of VH-, D-, and JH-gene segments indicating a dependency of the transferase mechanism upon the nuclease mechanism.