The Sequence of the Chromosomal Mouse /3-Globin Major Gene: Homologies in Capping, Splicing and

The entire nucleotide se- quence of a cloned j3-globinma’ gene derived from the BALB/c mouse is determined and it provides a basis for future comparison with other sequenced genes and a defined substrate for the development of direct tests of gene function.

Abstract

David A. Konkel, Shirley M. Tilghman* and Philip Leder Laboratory of Molecular Genetics National Institute of Child Health and Human Development Bethesda, Maryland 20014 Summary We have determined the entire nucleotide se- quence of a cloned j3-globinma’ gene derived from the BALB/c mouse. This sequence is 1567 bases long and includes the 5’ cap region as well as the presumptive poly(A) addition site of @globin mRNA. The sequence establishes the fact that the gene is encoded in three discontinuous seg- ments of DNA interrupted by two intervening se- quences and precisely locates each. The smaller intervening sequence, 116 bases long, occurs between Arg and Leu codons at codon positions 30 and 31. The larger intervening sequence of 646 bases also occurs between Arg and Leu codons, but at codon positions 104 and 105. There is striking homology between the borders of the two intervening sequences, but no extensive dyad symmetry. Furthermore, the DNA region that just precedes and overlaps the 5’ cap structure of the mRNA shows homology to corresponding regions in other eucaryotic genes including the late ade- novirus promoter. The 3’ untranslated sequence is closely homologous to that of the rabbit p- globin mRNA. The sequence thus allows us to identify several noncoding regions of potential importance for the expression and processing of genetic information. It also provides a basis for future comparison with other sequenced genes and a defined substrate for the development of direct tests of gene function. The adult BALB/c mouse coordinately expresses two P-globin genes encoding the two polypeptides /3-globinmaJ and @globin”‘“. These genes reside on the two Eco RI fragments of genomic DNA that have been cloned in the bacteriophage A (Tilghman et al., 1977; Tiemeier et al., 1978). Both genes appear to be interrupted by two intervening se- quences of DNA (ibid.) that are transcribed into the 1% globin mRNA precursor (Smith and Lingrel, 1978; Kinniburgh, Mertz and Ross, 1978; Tilghman et al., 1978b). Such structures have also been