From matthewk@XXXX Mon Oct 09  22:25:16  2000
Subject: vnc alleles
To: flybase-updates@XXXX
Personal communication from: Dianne Rees, Indiana University
Subject: vnc alleles
Dated: 1 August 1990
Background: The following information from Dianne Rees's Ph.D.
thesis (FBrf0070514) describes alleles she isolated in a screen for
female sterile mutation in the 67A \-- 67D interval. All
observations included here are Dianne's.
Information communicated:
gene:
vnc, variable nurse cells
map location:
67B \-- 67D based on deficiency complementation; maps between h
and th by recombination
complementation:
fails to complement Df(3L)AC1
complements Df(3L)29A6
complements RpS174
alleles:
vnc2 and vnc14
allele class:
hypomorphic, vnc2 slightly stronger than vnc14
phenotype:
viable, female sterile
The phenotypes associated with these mutations implicate the vnc
product in the control of cystocyte divisions within the
germarium.
Hemizygous vnc2/Df(3L)AC1, vnc14/Df(3L)AC1 and
homozygous vnc2 females produce no eggs. Homozygous vnc14
females produce a few flaccid eggs with abnormal chorions
(abnormal numbers of chorionic filaments and thin chorionic
membranes). vnc2/vnc14 heterozygotes produce eggs.
Hemizygous vnc2/Df(3L)AC1 and vnc14/Df(3L)AC1 ovaries are
small and comprised of tumorous egg chambers. Nuclei within these
egg chambers appear undifferentiated. Homozygous vnc2 and
vnc14 egg chambers range from too few through normal numbers to
too many nurse cells.
other info:
X-ray-induced on kniri-1 e1. vnc2 and vnc14 were among 15
female sterile alleles of this gene recovered in a screen of
3,000 chromosomes (the other 13 alleles have been lost). No
alleles of vnc were recovered in screens of 8,750 EMS-treated and
3,000 DEB-treated kniri-1 e1 chromosomes, raising the
possibility that this gene is sensitive to X-rays. In all cases
mutations were identified by their failure to complement
Df(3L)AC1 for female fertility. Differences in oogenic defects
among alleles argues against the 15 vnc alleles arising as a
cluster from a spontaneous premeiotic event.
Four additional female-sterile loci in the 67B \-- 67D interval (in
addition to alphaTub67C) were identified in these screens, but all
alleles of those four genes have been lost.