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Setting limits on homeotic gene function: restraint of Sex combs reduced activity by teashirt and other homeotic genes.
Author(s) -
Andrew D.J.,
Horner M.A.,
Petitt M.G.,
Smolik S.M.,
Scott M.P.
Publication year - 1994
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1994.tb06362.x
Subject(s) - homeotic gene , biology , gene , genetics , function (biology) , ultrabithorax , phenotype
Each of the homeotic genes of the HOM or HOX complexes is expressed in a limited domain along the anterior‐posterior axis. Each homeotic protein directs the formation of characteristic structures, such as wings or ribs. In flies, when a heat shock‐inducible homeotic gene is used to produce a homeotic protein in all cells of the embryo, only some cells respond by altering their fates. We have identified genes that limit where the homeotic gene Sex combs reduced (Scr) can affect cell fates in the Drosophila embryo. In the abdominal cuticle Scr is prevented from inducing prothoracic structures by the three bithorax complex (BX‐C) homeotic genes. However, two of the BX‐C homeotic genes, Ultrabithorax (Ubx) and abdominal‐A (abd‐A), have no effect on the ability of Scr to direct the formation of salivary glands. Instead, salivary gland induction by Scr is limited in the trunk by the homeotic gene teashirt (tsh) and in the last abdominal segment by the third BX‐C gene, Abdominal‐B (AbdB). Therefore, spatial restrictions on homeotic gene activity differ between tissues and result both from the regulation of homeotic gene transcription and from restraints on where homeotic proteins can function.