Mitotic recombination in germ cells generated two major histocompatibility complex mutant genes shown to be identical by RNA sequence analysis: Kbm9 and Kbm6.

Abstract

Kbm9 sequence is identical to that of another independently arising MHC mutant gene, Kb". As both the Kbm9 and Kb" genes were generated by recombination between the Kb and Q4 genes, our data indicate that the identical genetic interactions have occurred at least twice. The relatively large extent of identity between Q4 and Kb may be responsible for frequent recombination between the two genes. The parents of the original bm9 mutant mice had five identical mutant offspring, which can be explained by mitotic recombination in the germ cells, producing gonadal mosaicism in the C57BL/6 mother.Thus, mitotic recombination, and not meiotic recombination, appears to be responsible for the formation of at least some of the Kb mutants. Such a mechanism probably plays a major role in the generation of diversity in the major histocompatibility complex.

Nucleotide sequence of the androgen‐dependent arginine esterase mRNA of canine prostate

“…mRNA not encoded in the cDNA clone pAgE400, we used the RNA sequencing and cDNA sequencing procedures of Geliebter et al [12] based on the utilization of complementary oligonucleotide primers and primer extension. The whole sequence strategy is illustrated in fig.1.…”

“…The oligonucleotide primers were chemically synthesized using a Biosearch model '8700 DNA synthesizer (New Brunswick Scientific). These primers were labeled with [y-32P]ATP (Amersham, 5000 Ci/mmol) using T.I polynucleotide kinase (Bethesda Research Laboratories) as described by Geliebter et al [12]. The first primer 5 '-CCCTGGGTG AAAAATCGJ ' was complementary to the mRNA sequence from nucleotides 523 to 539 in fig.2.…”

“…The mixture was then left standing at room temperature for 30 min. The reverse transcription reaction was performed as described [12] with the exception that 7-deaza-2 ' -deoxyguanosine 5 ' -triphosphate from Pharmacia was substituted for dGTP. Furthermore, RAV-2 reverse transcriptase from Amersham was used with final concentrations of each ddNTP from Pharmacia (0.16 mM ddATP; 0.08 mM ddGTP, ddCTP and ddTTP).…”

“…The reverse transcription reaction was then performed at 50°C for 45 min with 150 ~1 reverse transcription buffer [12] containing 35-40 U RAV-2 reverse transcriptase. The cDNA generated by primer extension was extracted sequentially with equal volumes of phenol, then phenol/chloroform (1: 1) and finally chloroform.…”

“…The RNA: cDNA hybrids were denatured in boiling water for 5 min. Thereafter '*Plabeled oligonucleotide primers (5, 6, 7 or 8) were annealed to the cDNA and were extended with DNA polymerase I (Klenow fragment) from Amersham in the presence of dNTPs and ddNTPs [12]. The gels used for RNA and cDNA sequencing contained 5% acrylamide and 7 M urea.…”