Isolation and characterization of a genomic clone for the gene of an insect molting enzyme, chitinase

Genomic clones for a chitinolytic enzyme were isolated from a library of Sau 3A digested DNA from the tobacco hornworm, Manduca sexta, using a previously isolated chitinase cDNA clone as a probe [Kramer et al., Insect Biochem. Melee. Biol. 23, 691-701 (1993)], Restriction enzyme mapping and Southern blot analysis of four genomic clones suggested that these are overlapping clones, Sequence analysis of the genomic clones and Southern blot analysis of total genomic DNA also suggest that the M. sexta genome has only one chitinase gene detectable by the cDNA probe, This gene is organized into at least 11 exons in a region spanning >11 kb. The sequenced M. sexta chitinase gene has a series of exons corresponding to identifiable structural/functional regions of the protein. Similarities in structure and organization between the M. sexta chitinase gene and chitinase genes from other sources are described.