Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

DNA Sequences Mediating Class Switching in α-Immunoglobulins

Mark M. Davis, Stuart K. Kim and Leroy E. Hood
Science
New Series, Vol. 209, No. 4463, Recombinant DNA (Sep. 19, 1980), pp. 1360-1365
Stable URL: http://www.jstor.org/stable/1685195
Page Count: 6
  • More info
  • Cite this Item
DNA Sequences Mediating Class Switching in α-Immunoglobulins
Preview not available

Abstract

Immunoglobulin class switching involves specific DNA rearrangements of the gene segments coding for heavy chain constant regions (C$_{\text{H}}$) during B lymphocyte differentiation. In two different cases of C$_{\mu}$ to C$_{\alpha}$ switching examined here (T15 and M603) and one taken from the literature (MC101), three different sites on the 5$^{\prime}$ side of C$_{\mu}$ and three different sites on the 5$^{\prime}$ side of C$_{\alpha}$ are joined together in the process of C$_{\text{H}}$ switching. The sequences surrounding the three germ-line C$_{\alpha}$ sites of recombination are highly conserved blocks of 30 nucleotides that may serve as recognition sequences for C$_{\text{H}}$ switching to the C$_{\alpha}$ gene. This putative recognition sequence is repeated 17 times in approximately 1400 nucleotides of the germ-line C$_{\alpha}$ 5$^{\prime}$ flanking sequence. The lack of homology between this C$_{\alpha}$ sequence and sequences reported for the C$_{\gamma 1}$ and C$_{\gamma 2\text{b}}$ switch sites suggests that heavy chain switching is mediated by class-specific recognition sequences and, presumably, class-specific regulatory mechanisms. In addition, it appears that in one example (MC101) C$_{\text{H}}$ switching progressed from C$_{\mu}$ to C$_{\alpha}$ to C$_{\gamma 1}$. This switching pathway may present difficulties for the simple deletional model of C$_{\text{H}}$ switching.

Page Thumbnails

  • Thumbnail: Page 
1360
    1360
  • Thumbnail: Page 
1361
    1361
  • Thumbnail: Page 
1362
    1362
  • Thumbnail: Page 
1363
    1363
  • Thumbnail: Page 
1364
    1364
  • Thumbnail: Page 
1365
    1365