Discrete transcripts encode multiple chitinase isoforms in Brugian microfilariae.
The blood-borne microfilariae of the Brugian nematodes produce multiple isoforms of chitinase, whose expression is coincident with the onset of microfilarial infectivity for mosquitoes. A single cDNA sequence was previously obtained by screening a Brugia malayi microfilarial cDNA library, yet two chitinase isozymes are readily distinguished in this species. In this paper, we present evidence for the existence of multiple transcripts encoding Brugian microfilarial chitinases. Using primers based on the previously-sequenced cDNA clone, we amplified and sequenced two discrete products from B. malayi microfilarial RNA by RT-PCR. While the shorter fragment was nearly identical to the previously sequenced cDNA, the larger fragment contained an extra copy of a serine/threonine-rich repeat. RNAse protection assays were used to demonstrate that both sequences represent true transcripts, and not PCR artifacts. Using primers based on the B.malayi sequence, two novel sequences were generated by RT-PCR from B. pahangi microfilariae. Homologous and cross-species RNAse protection assays verified that multiple transcripts also encode chitinase isozymes in B. pahangi microfilariae.
Department of Biology, Tufts University, Medford, MA 02155, USA.
K
K
Arnold
A
A
Venegas
C
C
Houseweart
J A
JA
Fuhrman
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002009:Brugia / Q000201:enzymology* / Q000235:genetics* / Q000254:growth & development; D017178:Brugia malayi / Q000201:enzymology / Q000235:genetics; D017179:Brugia pahangi / Q000201:enzymology / Q000235:genetics; D002688:Chitinases / Q000235:genetics*; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D018509:DNA, Helminth / Q000235:genetics; D005091:Exons; D007438:Introns; D007527:Isoenzymes / Q000235:genetics*; D008842:Microfilariae / Q000201:enzymology / Q000235:genetics; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid
D017931:DNA Primers; D018076:DNA, Complementary; D018509:DNA, Helminth; D007527:Isoenzymes; D002688:Chitinases