TY - JOUR
T1 - Involvement of a particular species of beta-tubulin (beta3) in conidial development in aspergillus nidulans
AU - Weatherbee, James A.
AU - May, Gregory S.
AU - Gambino, John
AU - Morris, N. Ronald
PY - 1985/9/1
Y1 - 1985/9/1
N2 - Strains of Aspergillus containing the benA22 mutation are resistant to benomyl for vegetative growth but do not produce conidia. To test whether conidiation involved an additional benomyl-sensitive tubulin (i.e., was mediated by a tubulin other than the tubulins coded for by the benA locus), a collection of mutants was produced that formed conidia in the presence of benomyl, i.e., were conidiation-resistant (CR−) mutants. We analyzed the tubulins of these CR− mutants using two-dimensional gel electrophoresis and found that the mutants lacked one species of beta-tubulin (designated beta3). We have examined two of these mutants in detail. In crosses with strains containing wild-type tubulins, we found that the absence of the beta3-tubulin co-segregated perfectly with the CR− phenotype. In diploids containing both the benA22 and CR− mutations, we found that the CR− phenotype was recessive and that beta3-tubulin was present on two-dimensional gels of tubulins prepared from these diploids. In another set of crosses, these two CR− strains and seven others were first made auxotrophic for uridine and then crossed against strains that had homologously integrated a plasmid containing an incomplete internal fragment of the beta3-tubulin gene and the pyr4 gene of Neurospora crassa (which confers uridine prototrophy on transformants). If the CR− phenotype were produced by a mutation in a gene distinct from the structural gene for beta3-tubulin (designated the tubC gene), then crossing over should have produced some CR+ segregants among the uridine auxotrophic progeny of the second cross. All of the uridine auxotrophs from this type of cross, however, showed the CR− phenotype, suggesting that the mutation in these strains is at or closely linked to the tubC locus. The most obvious explanation of these results is that beta3-tubulin is oridinarily used during conidiation and the presence of this species of beta-tubulin renders conidiation sensitive to benomyl. In the CR− mutants, beta3-tubulin is absent, and in the presence of the benA22 mutation the benomyl-resistant beta1- and/or beta2-tubulin substitutes for beta3 to make conidiation benomyl resistant. We discuss these results and give two models to explain the interactions between these betatubulin species.
AB - Strains of Aspergillus containing the benA22 mutation are resistant to benomyl for vegetative growth but do not produce conidia. To test whether conidiation involved an additional benomyl-sensitive tubulin (i.e., was mediated by a tubulin other than the tubulins coded for by the benA locus), a collection of mutants was produced that formed conidia in the presence of benomyl, i.e., were conidiation-resistant (CR−) mutants. We analyzed the tubulins of these CR− mutants using two-dimensional gel electrophoresis and found that the mutants lacked one species of beta-tubulin (designated beta3). We have examined two of these mutants in detail. In crosses with strains containing wild-type tubulins, we found that the absence of the beta3-tubulin co-segregated perfectly with the CR− phenotype. In diploids containing both the benA22 and CR− mutations, we found that the CR− phenotype was recessive and that beta3-tubulin was present on two-dimensional gels of tubulins prepared from these diploids. In another set of crosses, these two CR− strains and seven others were first made auxotrophic for uridine and then crossed against strains that had homologously integrated a plasmid containing an incomplete internal fragment of the beta3-tubulin gene and the pyr4 gene of Neurospora crassa (which confers uridine prototrophy on transformants). If the CR− phenotype were produced by a mutation in a gene distinct from the structural gene for beta3-tubulin (designated the tubC gene), then crossing over should have produced some CR+ segregants among the uridine auxotrophic progeny of the second cross. All of the uridine auxotrophs from this type of cross, however, showed the CR− phenotype, suggesting that the mutation in these strains is at or closely linked to the tubC locus. The most obvious explanation of these results is that beta3-tubulin is oridinarily used during conidiation and the presence of this species of beta-tubulin renders conidiation sensitive to benomyl. In the CR− mutants, beta3-tubulin is absent, and in the presence of the benA22 mutation the benomyl-resistant beta1- and/or beta2-tubulin substitutes for beta3 to make conidiation benomyl resistant. We discuss these results and give two models to explain the interactions between these betatubulin species.
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U2 - 10.1083/jcb.101.3.706
DO - 10.1083/jcb.101.3.706
M3 - Article
C2 - 3897246
AN - SCOPUS:0022236914
SN - 0021-9525
VL - 101
SP - 706
EP - 711
JO - Journal of Cell Biology
JF - Journal of Cell Biology
IS - 3
ER -