Subject: M(3)S32 and M(3)86D correspond to RpS25
M(3)S32 and M(3)86D correspond to RpS25
Kevin Cook
Bloomington Stock Center, Indiana University
I mapped the M(3)S321 mutation from Bloomington stock 537 by first 
crossing it to a stock carrying the ru1 h1 th1 st1 cu1 
sr1 es ca1 chromosome, then backcrossing female progeny to the 
same stock and scoring rates of recombination between the Minute 
phenotype and the other markers.  In these crosses, I found that the 
M(3)S321 chromosome failed to complement cu1.  The Minute 
phenotype mapped between st and sr.
Since Df(3R)M86D (86D1-2;86D3-4) deletes the Minute M(3)86D and cu, I 
suspected that M(3)S321 might also be a deletion in the same 
region.  I found that M(3)S321 was lethal in combination with 
Df(3R)ED5506 (86C7;86D5), Df(3R)Exel6159 (86C3;86C7), Df(3R)ED5514 
(86C7;86E11) or Df(3R)ED5518 (86C7;86E13).  Only Df(3R)ED5514 and 
Df(3R)ED5518 delete ribosomal protein genes, the only class of genes 
demonstrated to correspond to Minutes. The other two deletions occupy 
more proximal positions.  This again suggested M(3)S321 might be a deletion.
My polytene chromosome squashes showed that the M(3)S321 chromosome 
carries a deletion of 86C8-13;86D8-E1 (the 86C7,8 doublet was 
present, 86C13 was absent, 86D8 was absent and the 86E1,2 doublet was 
present).  Consequently, the M(3)S321 mutation should be renamed to 
indicate that it is a deletion.  I suggest the name Df(3R)MS32.
Df(3R)MS32 complemented pros10409, pros17, Df(3R)Exel9018 
(86E2;86E4), Df(3R)Exel7308 (86E1;86E8) and Df(3R)ED5516 
(86D8;86E13).  These observations demonstrated that the deletion 
certainly ends proximal to pros, but likely ends even farther proximally.
Df(3R)MS32 complemented the P{XP}nocturnind05983 and 
P{EPgy2}TctpEY09182 insertion chromosomes, indicating that the 
recessive lethality of these chromosomes is unrelated to these insertions.
Df(3R)ED5514 and Df(3R)ED5518 delete the closely-linked ribosomal 
protein genes RpS25 and RpL3 (release 4 predicted position 
86D8).  The cytology of Df(3R)MS32 is consistent with it deleting 
these genes as well.  Since the P{Supor-P}RpL3KG05440 insertion 
disrupts an exon common to all RpL3 transcripts (as shown on GBrowse) 
and the intronic PBac{RB}e03180 insertion fails to complement 
P{Supor-P}RpL3KG05440, both mutations disrupt RpL3 
function.  Neither insertion shows a Minute phenotype.  This 
indicates that the most likely candidate for the Minute locus in this 
chromosomal region is RpS25.  Consequently, both M(3)86D and M(3)S32 
should be considered synonyms for RpS25.