Nucleic Acids Research, 1991, Vol. 19, No. 23 6475-6480
© 1991
MOLECULAR BIOLOGY |
Spontaneous deletions in lg heavy chain genes: flanking sequences influence splice site selection
Department of Cellular and Molecular Biophysical Studies, Columbia University New York, NY 10032 *Department of Microbiology and Molecular Genetics and the Molecular Biology Institute, University of California Los Angeles Los Angeles, CA 90024, USA
*To whom correspondence should be addressed
Received August 28, 1991. Accepted November 5, 1991.
The cell line G403.4.7, isolated as a spontaneous variant of the MPC-11 derived myeloma G403.4, produces a truncated
2b HC protein, but no light chain (LC), and a single
2b specific transcript of 2.4kb. This
2b transcript consists of the VDJ and CH1 exons, the CH1 to Hinge (Hi) intervening sequence (IVS) and Hi exon, part of the IVS between the two membrane exons M1 and M2, and most of the membrane 3' untranslated (UT) region. Even though the mature mRNA contains intronic sequences, it is abundant in the cytoplasm. Analysis of the
2b genomic organization reveals that this unusual transcript results in part from two genomic deletions of 2.5kb and 588bp and in part from an altered splicing pattern. This altered splicing pattern is probably a consequence of the sequence alterations resulting from the genomic deletions. Analysis of these events provides some interesting insights into the mechanism of splice site selection and the evolution of introns and exons.