Concerted evolution of class I genes in the major histocompatibility complex of murine rodents.
Full-length cDNA sequences of two class I major histocompatibility complex molecules from the DA strain of Rattus norvegicus are reported. One codes for the classical class I restriction element RT1.Aa, which maps to the locus in the rat major histocompatibility complex homologous to H-2K in the mouse. The other probably codes for a soluble nonclassical class I molecule present in DA rat serum; a short deletion in the fifth exon implies that the translated product will terminate in the membrane-spanning region. These sequences have been compared with mouse classical class I sequences as well as with three published rat class I cDNA partial sequences. The results show, first, that "locus-specific" substitutions from the H-2K, H-2D, and H-2L data set are scrambled in the RT1.Aa molecule; a majority of these substitutions have H-2D/L-specific features. Second, the data show that the four rat sequences are strikingly similar to one another regardless of locus or haplotype of origin; they share a number of apparently species-specific features that distinguish them all from mouse classical class I sequences, which likewise share distinctive features of their own. The results suggest that segmental sequence exchange plays a major role in determining the evolution of sequence in class I major histocompatibility complex molecules.
Rada
C
C
Department of Immunology, Institute of Animal Physiology and Genetics Research, Cambridge Research Station, Babraham, United Kingdom.
Lorenzi
R
R
Powis
S J
SJ
van den Bogaerde
J
J
Parham
P
P
Howard
J C
JC
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D005075:Biological Evolution; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D005805:Genes, MHC Class I; D007256:Information Systems; D051379:Mice; D008969:Molecular Sequence Data; D015345:Oligonucleotide Probes; D051381:Rats; D012689:Sequence Homology, Nucleic Acid
D015345:Oligonucleotide Probes; D004247:DNA