De. Cummings et al., CLONING OF A MOUSE PROTEIN-KINASE-A CATALYTIC SUBUNIT PSEUDOGENE AND CHROMOSOMAL MAPPING OF C-SUBUNIT ISOFORMS, Mammalian genome, 5(11), 1994, pp. 701-706
Two isoforms of the protein kinase A catalytic subunit, C alpha and C
beta, have previously been described in the mouse. We now report the c
loning and characterization of a novel C-related sequence, Cx, from a
murine genomic library. Cx is 89.8% identical to part of the C alpha c
oding region, but lacks all of the introns present in this gene, sugge
sting that it arose via retroposition. The existence of several frames
hift mutations, premature termination codons, and missense mutations a
t critical sites confirms that it is a pseudogene. Furthermore, we are
unable to detect any expression. Homology with functional protein kin
ase genes commences exactly at the first intron splice junction in C a
lpha, downstream of the expected translational start codon. Cx is also
truncated at its 3' end by the interposition of two distinct, contigu
ous LINE-1 elements. By fluorescence in situ hybridization, we demonst
rate that Cx is located on the X Chromosome (Chr), at band F3. This is
displaced from its functional homologs, C alpha and C beta, which we
map to mouse Chrs 8 (band C3) and 3 (band H3), respectively.