Alternative Use of 5′ Exons in the Specification of Ly-5 Isoforms Distinguishing Hematopoietic Cell Lineages

• Published in: Proceedings of the National Academy of Sciences - PNAS 1987-08, Vol.84 (15), p.5364-5368
• Main Authors: Saga, Yumiko, Tung, Jwu-Sheng, Shen, Fung-Win, Boyse, Edward A.
• Format: Article
• Language: English
• Subjects: Amino acids; Animals; B lymphocytes; Base Sequence; Biological and medical sciences; Complementary DNA; DNA - analysis; Endonucleases - metabolism; Exons; Fundamental and applied biological sciences. Psychology; Gene expression; Genomics; Hematopoiesis; Histocompatibility Antigens - genetics; Leukocyte Common Antigens; Messenger RNA; Mice; Molecular and cellular biology; Molecular genetics; Protein isoforms; RNA; RNA probes; RNA Splicing; Single-Strand Specific DNA and RNA Endonucleases; T lymphocytes; Transcription, Genetic
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.84.15.5364

Previous inferences that Ly-5 glycoprotein isoforms of murine hematopoietic cells are generated by alternative splicing of primary transcripts of a single Ly-5 gene are supported by the present study. A cDNA library was prepared from B cells by extension from primer representing a known T-cell cDNA sequence. Three different Ly-5 clones from this library included sequences missing in T-cell cDNA clones. From the constitution of cDNA clones and of the Ly-5 gene, and from S1 nuclease mapping, it is concluded that at least two exons, provisionally numbered Ex-6(B) and Ex-7(B), in the 5′-proximal region are mainly represented in mRNA of the B-cell lines examined but not of the T-cell lines examined. Also, exons 1 and 2 appear to be used alternatively in different species of B-cell mRNA and probably also in different species of T-cell mRNA.