Subject: Characterization of deletions and Minutes in chromosomal region 99-100
Characterization of deletions and Minutes in chromosomal region 99-100
Kevin Cook
Bloomington Drosophila Stock Center
Indiana University
I complementation tested Df(3R)01215, Df(3R)tll-e, Df(3R)tll-g,
Df(3R)awd-KRB and Df(3R)X3F against mutations in chromosomal region
99-100 to determine their endpoints. The Df(3R)X3F chromosome carried
P{RP49} to rescue the Minute phenotype of RpL32 deleted by the
Df(3R)X3F aberration. I scored complementation for lethality and
female sterility. Unless otherwise noted, complementing mutations
produced viable adults and fertile females, and noncomplementing
mutations resulted in lethality.
Df(3R)01215 (Bloomington stock 5424) failed to complement kaysro-1
(3091) and kay1 (3105), but complemented ca1 (459),
eIF2B-alphaEY03991 (16584), AxnEY10228 (17649) and spn-A1 (3322).
Df(3R)X3F, P{RP49} (2352) failed to complement eIF2B-alphaEY03991
(16584), CG7920EY00580 (15298), CG7950e02275 (18033),
AxnEY10228 (17649) and spn-A1 (3322), but complemented ca1
(459), Mlc2E38 (4415), hdcFus-6 (10695), hdcB4-3-20 (10900),
hdcEY02460 (15418), hdcBG00237 (12410), hdcKG09851 (16493),
wts3-17 (7052), tlll49 (7093) and tll1 (2729).
Df(3R)tll-g (2599) failed to complement Fer1HCH00451 (11497),
Fer2LCHneo60 (10296), Fer2LCH00035 (11483), wts3-17 (7052),
tlll49 (7093), tll1 (2729), dco3 (2455), dco2 (2458) and
l(3)0252102521 (11570), but complemented spn-A1 (3322), Mlc2E38
(4415),hdcFus-6 (10695), hdcB4-3-20 (10900), hdcEY02460
(15418), hdcBG00237 (12410), hdcKG09851 (16493), l(3)rM731rM731
(12165), pygoS28 (7208), pygoS123 (7209), Med13 (7340), ttk1
(4163) and ttk1e11 (4164).
Df(3R)tll-e (5415) failed to complement tlll49 (7093), tll1
(2729), dco3 (2455), dco2 (2458) and l(3)rM731rM731 (12165),
but complemented hdcFus-6 (10695), hdcB4-3-20 (10900),
hdcEY02460 (15418), hdcBG00237 (12410), hdcKG09851 (16493),
Fer1HCH00451 (11497), Fer2LCHneo60 (10296), Fer2LCH00035
(11483), pygoS28 (7208), pygoS123 (7209), Med13 (7340), Med5
(9006), Med1 (9033), ttk1 (4163), ttk1e11 (4164), wts3-17
(7052), awdj2A4 (12167), awdKRS6 (9035) and l(3)0252102521 (11570).
Df(3R)awd-KRB (3369) failed to complement ttk1 (4163), ttk1e11
(4164), awdj2A4 (12167) and awdKRS6 (9035), but complemented
dco3 (2455), dco2 (2458), l(3)rM731rM731 (12165), pygoS28
(7208), pygoS123 (7209), Med13 (7340), Med5 (9006), Med1
(9033). Df(3R)awd-KRB also complemented the male sterility of
heph03429 (11589) and heph2 (635).
I obtained the following complementation results in control crosses.
pygoS28 (7208) failed to complement pygoS123 (7209). Med13
(7340), Med5 (9006) and Med1 (9033) failed to complement in all
pairwise combinations. heph03429 (11589) and heph2 (635) failed
to complement for male sterility. hdcBG00237 (12410) failed to
complement hdcFus-6 (10695), hdcKG09851 (16493), hdcEY02460
(15418) and hdcB4-3-20 (10900). hdcKG09851 (16493) failed to
complement hdcFus-6 (10695), hdcEY02460 (15418) and hdcB4-3-20
(10900). hdcEY02460 (15418) failed to complement hdcFus-6 (10695)
and hdcB4-3-20 (10900) for female sterility. hdcB4-3-20 (10900)
failed to complement hdcFus-6 (10695) for female sterility.
The following complementation results demonstrated that the
homozygous lethality of certain chromosomes carrying transposable
element insertions is not due to the lethality of the insertions
themselves.  P{lacW}Takr99Ds2222 (12161) complemented Df(3R)X3F
(2352).  P{SUPor-P}KG08927 (15149) complemented Df(3R)tll-g
(2599).  PBac{PB}CG31005c04819 (11672) complemented Df(3R)tll-e (5415).
Another goal of these crosses was to determine the correspondences of
ribosomal protein genes to Minute loci in this chromosomal region. By
comparing the genome map to the complementation data above, I could
position the ribosomal protein genes RpS8, RpS28a, RpL32, RpS7,
mRpS18C, mRpL32 and RpL6 in relation to the endpoints of Df(3R)01215,
Df(3R)X3F, Df(3R)tll-g, Df(3R)tll-e and Df(3R)awd-KRB. When I
compared this information to previous studies of region 99-100, I was
able to correlate Minute loci to ribosomal protein genes.
Kongsuwan et al. (1986) defined four Minute loci in region 99-100 by
segmental aneuploidy experiments: M(3)99B at 99B5-9, M(3)99D at
99D1-9, M(3)99E at 99E4-F1 and M(3)100CF at 100C-F. Kongsuwan et al.
(1985) showed that M(3)99D corresponds to RpL49 by rescuing the
M(3)99D phenotype with the RpL32 transgenic construct P{RP49}.
Heterozygous Df(3R)01215, Df(3R)tll-e, Df(3R)tll-g and Df(3R)awd-KRB
chromosomes do not give Minute phenotypes. As shown by my endpoint
analysis, the only ribosomal protein genes encompassed by these
deletions are the mitochondrial ribosomal protein genes mRpS18C and
mRpL32, which are deleted by Df(3R)tll-g and Df(3R)tll-e,
respectively. This demonstrates that heterozygosity for mRpS18a or
mRpL32 does not cause a Minute phenotype, and that neither of these
genes correlates with a previously-defined Minute.
Heterozygous Df(3R)X3F in combination with P{RP49} also does not give
a Minute phenotype. My breakpoint analysis shows that Df(3R)X3F
deletes both RpS28a and RpL32. Since P{RP49} rescues the Minute
phenotype of RpL32 heterozygosity, RpS28a must not be
haploinsufficient and cannot correlate with any of the
previously-defined Minutes.
The remaining ribosomal protein genes--S8, RpS7 and RpL6--lie in the
gaps in deletion coverage between Df(3R)01215, Df(3R)X3F,
Df(3R)tll-g, Df(3R)tll-e and Df(3R)awd-KRB. It is quite likely they
account for the remaining Minute loci M(3)99B, M(3)99E and M(3)100CF.
It is not surprising that the Minutes are not uncovered by simple
deletions recovered in the absence of chromosomal duplications, since
most Minutes are associated with haplosterility and/or haplolethality.
RpS8 lies distal to Df(3R)01215 and quite likely lies proximal to
Df(3R)X3F. In this position, it correlates quite well to M(3)99B.
RpS7 lies distal to Df(3R)X3F and proximal to Df(3R)tll-g. In this
position, it correlates to M(3)99E.
RpL6 lies distal to Df(3R)tll-e and proximal to Df(3R)awd-KRB. It
correlates to M(3)100CF.
References:
Kongsuwan, K., Yu, Q., Vincent, A., Frisardi, M.C., Rosbash, M.,
Lengyel, J.A., Merriam, J., 1985. "A Drosophila Minute gene encodes a
ribosomal protein". Nature  317:555-558 .
Kongsuwan, K., Dellavalle, R.P., Merriam, J.R., 1986. "Deficiency
analysis of the tip of chromosome 3R in Drosophila melanogaster".
Genetics  112:539-550 .