FB2026_01 , released March 12, 2026
FB2026_01 , released March 12, 2026
Allele: Dmel\sax2
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General Information
Symbol
Dmel\sax2
Species
D. melanogaster
Name
FlyBase ID
FBal0015143
Feature type
allele
Associated gene
Dmel\sax
Associated Insertion(s)
Carried in Construct
Key Links
Genomic Maps

Allele class

antimorphic allele - genetic evidence

hypomorphic allele - genetic evidence

neomorphic allele - genetic evidence

Mutagen
Nature of the Allele
Allele class

antimorphic allele - genetic evidence

(Twombly et al., 2009)

hypomorphic allele - genetic evidence

(Xie et al., 1994)

neomorphic allele - genetic evidence

(Nellen et al., 1994)
Mutagen
ethyl methanesulfonate
Progenitor genotype
Cytology
Description

Lesion in the kinase domain.

(Letsou et al., 1995)

Amino acid replacement: G412E.

(Brummel et al., 1994)

Amino acid replacement: G412E. G412 is a highly conserved amino acid of the kinase domain.

(Nellen et al., 1994)

Amino acid replacement: G?E. Amino acid 189 maps near the ATP binding site.

(Xie et al., 1994)
Mutations Mapped to the Genome
Curation Data
Type
Location
Additional Notes
References
point_mutation
2R:7,808,818..7,808,818 [+]
Nucleotide change:

G7808818A

Amino acid change:

G412E | sax-PA; G377E | sax-PB; G424E | sax-PC

Reported amino acid change:

G412E

Comment:

Site of nucleotide substitution in mutant inferred by FlyBase based on reported amino acid change.

(Brummel et al., 1994, Nellen et al., 1994, Xie et al., 1994)
Variant Molecular Consequences
Associated Sequence Data
DDBJ / EMBL / GenBank
DNA sequence
Protein sequence
 
UniProtKB/Swiss-Prot
    UniProtKB/TrEMBL
      Expression Data
      Reporter Expression
      Additional Information
      Statement
      Reference
       
      Marker for
      Reflects expression of
      Reporter construct used in assay
      Human Disease Associations
      Disease Ontology (DO) Annotations
      Models Based on Experimental Evidence ( 1 )
      Disease
      Evidence
      References
      model of  fibrodysplasia ossificans progressiva
      CEA
      (Twombly et al., 2009)
      Modifiers Based on Experimental Evidence ( 0 )
      Disease
      Interaction
      References
      Comments on Models/Modifiers Based on Experimental Evidence ( 0 )
       
      Disease-implicated variant(s)
       
      This allele represents a human variant implicated in disease.
      (Twombly et al., 2009)
      ACVR1:p.Gly356Asp
      (FlyBase curators, 2019-)
      Variants Synonym(s)
      Associated human disease model(s)
      External database links
      ClinVar: ACVR1_18310
      Comments concerning this variant
      Phenotypic Data
      Phenotypic Class

      female sterile | recessive

      (Schupbach and Wieschaus, 1989)

      lethal | maternal effect (with sax1rv1)

      (Twombly et al., 2009)

      lethal | maternal effect | recessive

      (Brummel et al., 1994)

      lethal - all die during embryonic stage | maternal effect

      (Nellen et al., 1994)

      lethal - all die during embryonic stage | maternal effect (with sax1)

      (Twombly et al., 2009)

      lethal - all die during embryonic stage | maternal effect | recessive

      (Twombly et al., 2009, Schupbach and Wieschaus, 1989)

      partially lethal - majority die | maternal effect (with Df(2R)H23)

      (Twombly et al., 2009)

      partially lethal - majority die | maternal effect (with Df(2R)P32a)

      (Twombly et al., 2009)

      some die during embryonic stage | maternal effect

      (Nellen et al., 1994)

      some die during embryonic stage | maternal effect (with Df(2R)H23)

      (Twombly et al., 2009)

      some die during embryonic stage | maternal effect (with Df(2R)P32a)

      (Twombly et al., 2009)

      some die during embryonic stage | maternal effect (with sax1)

      (Twombly et al., 2009)

      some die during embryonic stage | recessive | maternal effect | recessive

      (Twombly et al., 2009, Schupbach and Wieschaus, 1989)

      viable

      (Twombly et al., 2009)

      viable (with Df(2R)H23)

      (Twombly et al., 2009)

      viable (with Df(2R)sax1rv2)

      (Twombly et al., 2009)

      viable (with Df(2R)sax-H9)

      (Twombly et al., 2009)

      viable (with sax1)

      (Twombly et al., 2009)

      viable (with sax1rv1)

      (Twombly et al., 2009)

      viable (with sax1rv5)

      (Twombly et al., 2009)

      viable (with sax3)

      (Twombly et al., 2009)

      viable (with sax4)

      (Twombly et al., 2009)

      viable (with sax5)

      (Twombly et al., 2009)

      viable (with sax6)

      (Twombly et al., 2009)

      viable (with saxP)

      (Twombly et al., 2009)
      Phenotype Manifest In
      Detailed Description
      Statement
      Reference

      When crossed to wild-type males, homozygous sax2 or heterozygous sax1/sax2 females produce phenotypically normal eggs that die as embryos.

      The number of Kr-positive amnioserosa cells (the dorsal most embryonic fate) is reduced in the progeny of sax1/sax2 mutant mothers compared to wild-type embryos.

      (Twombly et al., 2009)

      sax1/sax2 mutant females generate embryos that show loss of the amnioserosa.

      (Rusch and Levine, 1997)

      sax1/sax2 individuals exhibit nearly wild type wings. When in combination with put135 heterozygotes most individuals lack the posterior cross vein.

      (Letsou et al., 1995)

      Mutant embryos show ventralization of dorsal cuticle, gut defects, severe reduction in the size of imaginal discs and anterior egg shell defects.

      (Brummel et al., 1994)

      Embryos from sax1/sax2 females show deletions of anterodorsal head structures and an internalization of the Filzkorper and the seventh and eighth abdominal segments. This partially ventralized phenotype is characteristic of embryos from mother homozygous for weak alleles of dpp or heterozygous for null dpp allele. Heterozygous females that are also heterozygous for dpphr56 or dpphr27, show markedly reduced viability (for dpphr56) or lethality (for dpphr27). The enhancement of the mutant phenotype extends to the phenotype of the embryos produced.

      (Nellen et al., 1994)

      The presence of sax2 in the mother causes dpphr27 to behave as a dominant lethal in the zygote.

      (Penton et al., 1994)

      Embryos from sax1/sax2 mothers have a deep dorsal cephalic furrow, and the germband does not extend to its full length dorsally.

      (Xie et al., 1994)

      Eggs derived from homozygous females cellularise normally but become abnormal at gastrulation. Germ band extension is abnormal. Posterior midgut invagination occurs at an abnormal dorsal position. There are abnormalities in the cuticle at the anterior and posterior ends. The phenotype resembles mutations of tsg, zen and weak alleles of dpp.

      (Schupbach and Wieschaus, 1989)
      External Data
      Interactions
      Show genetic interaction network for Enhancers & Suppressors
      Phenotypic Class
      Suppressed by
      Suppressor of
      Statement
      Reference

      sax1, Agam\gbb1gbb.PF, sax2 is a suppressor of visible phenotype of gbb4/gbb1

      (Fritsch et al., 2010)

      sax1, Agam\gbb2gbb.PF, sax2 is a suppressor of visible phenotype of gbb4/gbb1

      (Fritsch et al., 2010)

      sax2 is a suppressor of visible phenotype of upd1GMR.PB

      (Bach et al., 2003)

      sax[+]/sax2 is a suppressor of visible | heat sensitive phenotype of HC2.hs

      (Johannes and Preiss, 2002)
      NOT Suppressor of
      Statement
      Reference

      sax1, scwgbb.PF, sax2 is a non-suppressor of visible phenotype of gbb4/gbb1

      (Fritsch et al., 2010)
      Other
      Phenotype Manifest In
      Suppressor of
      Statement
      Reference

      sax1, Agam\gbb1gbb.PF, sax2 is a suppressor of wing vein phenotype of gbb4/gbb1

      (Fritsch et al., 2010)

      sax1, Agam\gbb2gbb.PF, sax2 is a suppressor of wing vein phenotype of gbb4/gbb1

      (Fritsch et al., 2010)

      sax2 is a suppressor of eye phenotype of upd1GMR.PB

      (Bach et al., 2003)

      sax[+]/sax2 is a suppressor of wing vein | ectopic | heat sensitive phenotype of HC2.hs

      (Johannes and Preiss, 2002)

      sax[+]/sax2 is a suppressor of wing | heat sensitive phenotype of HC2.hs

      (Johannes and Preiss, 2002)
      NOT Suppressor of
      Statement
      Reference

      sax1, scwgbb.PF, sax2 is a non-suppressor of wing vein phenotype of gbb4/gbb1

      (Fritsch et al., 2010)
      Other
      Additional Comments
      Genetic Interactions
      Statement
      Reference

      scwgbb.PF cannot rescue the wing vein defects of gbb1/gbb4 flies in a sax1/sax2 background.

      (Fritsch et al., 2010)

      The maternal effect lethal phenotype of homozygous sax2 or sax1/sax2 embryos can be significantly suppressed by paternal Dp(2;2)DTD48 or Dp(2;2)B16 duplications.

      The maternal effect lethal phenotype of sax2/Df(2R)H23 embryos is suppressed by paternal Dp(2;2)DTD48 or Dp(2;2)B16 duplications.

      When dpphr4/+ males are crossed to sax2/+ females, all the resulting dpphr4/+ progeny die. Similarly, any one of the paternal dppe87/+, dpphr56/+, dpphr90/+ or dpphr27/+ genotypes in combination with a maternal sax2/+ genotype results in increased dpp zygotic haplolethality in the progeny.

      The maternal enhancement of the dpphr4/+ zygotic haplolethality by sax2/+ is suppressed by either Dp(2;2)DTD48/+ or Dp(2;2)B16/.

      Strong maternal effect lethality is observed when trans-heterozygous Mad12 sax2 females are crossed with wild-type males.

      sax2 heterozygous mothers generate synthetic lethality when crossed to scwE1/+ males.

      sax2 heterozygous mothers generate synthetic lethality when crossed to scwE2/+ males.

      (Twombly et al., 2009)

      When the genetic background is heterozygous for sax2, any dpp mutant phenotype is more severe than expected. Maternal effect of sax2 can be rescued by extra dpp+, supplied by a duplication.

      (Brummel et al., 1994)

      Flies transheterozygous for dpphr27 or dpphr93 and sax1 or sax2 fail to eclose. sax mutants can be rescued by extra copies of dpp, dppSal20 or dppP6.5.

      (Xie et al., 1994)
      Xenogenetic Interactions
      Statement
      Reference

      Agam\gbb1gbb.PF and Agam\gbb2gbb.PF each partially rescue the wing vein defects of gbb1/gbb4 animals in a sax1/sax2 background; partial rescue of the posterior crossvein is seen and in addition loss of the distal tips of vein L5 and loss of the distal quarter of vein L4 are seen.

      (Fritsch et al., 2010)
      Complementation and Rescue Data
      Comments
      Images (0)
      Mutant
      Wild-type
      Stocks (0)
      Notes on Origin
      Discoverer
      External Crossreferences and Linkouts ( 0 )
      Synonyms and Secondary IDs (3)
      Reported As
      Symbol Synonym
      sax2
      (Fritsch et al., 2010, Twombly et al., 2009)
      saxHB18
      (Yip et al., 1997)
      saxHB
      (Johannes and Preiss, 2002)
      Name Synonyms
      Secondary FlyBase IDs
        References (17)