| The
Role of Bestrophin Genes in Drosophila Malpighian Tubules
Jennifer
Krueger
Marquette
University
Summer
Mentor: Dr. Edward Blumenthal
Osmoregulation
is necessary for the survival of all living organisms and can be influenced
by the expression of various genes. My research has focused on four Bestrophin
genes, which are known to be expressed as calcium-activated chloride channels
and are presumed to function in the Malpighian (renal) tubules of Drosophila.
A line of flies lacking a Bestrophin gene (dBest1) and a
line that has the gene reinserted into the genome were analyzed for their
ability to survive on 0.4 M NaCl and 0.8 M Sorbitol. Results showed salt
sensitivity in the dBest1 mutant line with about 80% of the flies dying
on salt, while 10% of the rescue line died over a seven day period. All
flies from both lines survived on 0.8 M Sorbitol over the same time period.
This indicated the presence of a salt-sensitive phenotype resulting from
the deletion of the dBest1 gene. Urine secretion assays were performed
to compare secretion rates of the Malpighian tubules of both lines. There
was no significant difference in secretion rate between the knockout and
rescue lines. Real Time PCR was used to quantify the relative amounts of
expression for the three of the Bestrophin genes in whole fly and
Malpighian tubule cDNA. Results showed that in the whole fly dBest1
and dBest2 were expressed at much higher levels than dBest3.
In contrast, dBest2 and dBest3 were expressed at high levels
in the Malpighian tubule. However, there was no evidence for the presence
of dBest1. Therefore, the observed salt sensitivity in the dBest1
mutant line must be due to the lack of dBest1 elsewhere in the fly. |
