RpII215: RNA polymeraseII-215 kd subunit
The structural gene encoding the 215 kd subunit of
RNA polymerase II [RNA nucleotidyl transferase (EC 18.104.22.168)].
This subunit highly conserved as inferred from the cross reaction of antiserum from the large subunit of calf RNA polymerase II with enzyme isolated from Drosophila as well as that
from yeast and wheat germ (Carrol and Stollar, 1983, J. Mol.
Biol. 170: 777-90); also amino-acid sequence homology
detected with the β' subunit of E. coli RNA polymerase (Biggs,
Searles, and Greenleaf, 1985, Cell 42: 611-21). Dosage compensated at the level of transcription (Faust, Penkawitz-Pohl,
Falkenberg, Gasch, Biabjah, Young, and Bautz, 1986, EMBO J.
This allele was selected as an amanitin resistant
mutation; RpII2154/+ females produce equal amounts or
amanitin-sensitive and -resistant enzyme and are themselves
amanitin resistant. Generally a viable allele, but survival
in combination with RpII21563 and RpII21586 reduced, and with
RpII21551 and RpII21578 survival is zero. RNA polymerase isolated from embryos homozygous for this allele is 250 times
less sensitive to inhibition by alpha amanitin than that from
wild type; resistance attributable to reduced amanitin binding; otherwise RNA polymerase normal in all respects except
that there is some reduction in activity in the presence of
Mg2+; stable to thermal denaturation (Coulter and Greenleaf,
1982, J. Biol. Chem. 157: 1945-52). Flies carrying both
RpII2154 and RpII215+ display an Ultrabithorax-like phenotype,
with enlarged halteres, and an enhancing effect on expression
of Ubx [Greenleaf et al., 1980; Voelker, Wisely, Huang, and
Gyurkovics, 1985, Mol. Gen. Genet. 201: 437-45 (fig.)].
Measurements of haltere size in TM6/+ females of various constitutions produced the following: 4/+/+ > 4/+ > 4/4/+ > 4/4 =
4/0 = +/+. The haltere effect of RpII2154 is abolished in
heteroallelic combination with RpII2157, RpII215H1, and
RpII215K2. RpII2154 decreases the Ubx effect of RpII215Ubl.
Heterozygotes also exhibit increased numbers of duplicated
bristles in Dl/+ (Mortin et al.). Males carrying RpII2154 on
their X plus a normal allele on Dp(1;Y)BS-v+y+ are nearly
sterile, and those carrying the normal allele instead on
Dp(1;2)v65b are sterile (Voelker et al.).
Cold-sensitive lethal; survives at 28 with nearly
wild-type viability, but is lethal at lower temperatures.
Surviving males are fertile, whereas homozygous females are
sterile. Displays slight increase in haltere size in
RpII2157/+; Ubx/+ females. Lethal in combination with
RpII215Ubl. Ubx effect inhibited in trans heterozygotes with
other interacting alleles. In viable heterozygotes, causes an
increase in the number of duplicated bristles in Dl/+ and, in
males carrying a duplicated normal allele, produces sex combs
on the middle legs.
Homozygous lethal; RpII215106/RpII215106 females
with a duplication for RpII215+ display about 50% normal viability, and are fertile when crossed to wild type, but nearly
sterile in crosses to RpII215Ubl males with a duplication for
RpII215+; all surviving progeny of the latter cross display a
hyperabdominal-like phenotype; the females lack metathoracic
legs and/or halteres in addition to having extra abdominal
tissue; this phenotype barely detectable in offspring of
crosses to normal males.
Homozygous lethal; RpII215109/RpII215109
/Dp(1;1)RpII215+ females display about 50% normal viability,
are fertile when crossed to wild type, but fertility only 50%
normal in crosses to RpII215Ubl/Dp(1;1)RpII215+ males; offspring from the latter cross have darkened eyes, thin bristles,
and are sterile.
Homozygous and hemizygous viable. Exhibits slight
enhancement of Ubx when heterozygous to + but not in heteroallelic combination with any of the interacting mutant alleles;
it decreases the enhancing effects of RpII215Ubl. Increases
the number of duplicated bristles of Dl/+ in all genotypes.
Temperature-sensitive recessive lethal; flies survive at 19 but not at 29. Although not displaying the Ubx-enhancing effect in combination with +, it does inhibit the
effect of RpII2154 at 29 but not at 25 or 19.
Homozygous and hemizygous viable; homozygous females
sterile. Exhibits slight enhancement of Ubx when heterozygous
to + but not in heteroallelic combination with any of the
interacting mutant alleles; it decreases the enhancing effects
of RpII215Ubl. Increases the number of duplicated bristles of
Dl/+ in all genotypes. Temperature-sensitive period for
effects on both Ubx and Dl from third larval instar until
Encodes a heat labile RNA polymerase subunit, as
measured in vitro (Coulter and Greenleaf, 1982, J. Biol. Chem.
157: 1945-52) and by sterilizing effects on females and
lethal effects on embryos. Females shifted from 22 to 29
become sterile, although their eggs laid during the first 24
hr appear normal morphologically; after 24 hr, embryonic
development is visibly abnormal. Embryonic abnormalities
include holes in the ventral cuticle and abnormal pharyngeal
structures. Partial rescue of the sterility can be achieved
by shifting newly laid eggs to 22 or by fertilization of eggs
of RpII215ts females with wild-type sperm; the degree of rescue decreases as the time that the females have been held at
29 increases. Abnormalities of embryos dying despite rescue
attempts mimic the phenotypes of pair-rule and segment-polarity mutants; surviving adults resemble Hab in lacking one
or both halteres and metathoracic legs. In
RpII215ts/+//RpII215ts/0 gynandromorphs, the RpII215ts/0 tissue appears to occupy more territory than expected, as though
it had a proliferative advantage over the RpII215ts/+ tissue
(Mortin, Perrimon, and Bonner, 1985, Mol. Gen. Genet.
Homozygous and hemizygous lethal. Heterozygotes
mimic Ubx in adding several hairs to and enlarging the capitellum of the haltere; females homozygous for RpII215Ubl, surviving by virtue of a duplication for RpII215+, more severely
affected with capitellum approximately three times the size of
that observed in RpII215Ubl/+ and with two or more rows of
bristles; about 10% normal viability; poorly fertile in
crosses to wild type; sterile when crossed to RpII215Ubl males
with a duplication of RpII215+. Similarly males with one
mutant and one normal allele are more extreme than females
with one mutant and two normal alleles. Acts as a dosage sensitive enhancer of Ubx, transforming halteres into wing-like
structures; enhancement by RpII215Ubl/RpII215Ubl/+ >
RpII215Ubl/+ > RpII215Ubl/+/+. RpII215Ubl/+ interacts with
heterozygotes for bx3 and bx7 but not bx1 to produce enlarged
capitellum, and with bxd100/+ to transform halteres into
wing-like structures; extra doses of Ubx+ counteract the
enhancing effects of RpII215Ubl. A second interaction with
Ubx/+ is the production of miscadestral-like pigmentation.
Ubx enhancement by RpII215Ubl reduced in trans heterozygotes
with other interacting alleles (Mortin et al.). Furthermore
in RpII215Ubl/+//RpII215Ubl/0 gynandromorphs, the X0 tissue is
without any RpII215Ubl phenotype, displaying neither enlarged
halteres nor enhancement of Ubx expression, whereas the XX
tissue exhibits both enlarged halteres and Ubx enhancement
(Mortin, Perrimon, and Bonner, 1985, Mol. Gen. Genet.
201: 437-45). RpII215Ubl/+ also display increased frequencies of duplicated bristles in Dl/+, and in some crosses
causes Sb/+ flies to exhibit shortened and broadened wings
whose longitudinal veins fail to reach the margin (Mortin et
al.). RpII215Ubl in heterozygous combination with deficiencies for either ct or sno is lethal and with lethal alleles of
ct produces a strong cut phenotype; produces a mutant phenotype of allele specific severity in heterozygous combination
with deficiencies for or lethal alleles of br, N, dm, slc, bi,
oc, m, sd, and sw; interacts with heterozygotes for mutant
alleles of oc, sno, and sw, but not the others; no interaction
with dor, sn, ras, or g deficiencies. Influence of the maternal genotype apparent since patroclinous RpII215Ubl/Y and
RpII215Ubl/0 males from non mutant mothers survive at 20% the
expected rate; they are phenotypically normal but are sterile
(Voelker et al.).