Figure 1.

Generation of null alleles of the acf1 gene. (A) The Drosophila acf1 gene. The structure of the acf1 gene and the location of the transposon insertions in EP(3)1181 and EY08629 are shown. The acf1¹ allele was generated by imprecise excision of acf1^EP(3)1181, in which 499 bp of the first intron and second exon has been replaced by an 11-bp sequence from the P-element. The allele acf1³ was generated by imprecise excision of acf^EP(3)1181, in which 83 bp entirely within the first intron have been replaced by a 15-bp sequence from the P-element. The acf1² allele, in which 871 bp of the acf1 promoter and 5′ transcribed region is deleted, was generated by imprecise excision of acf1^EY08629. The acf1⁴ allele was generated by precise excision of acf1^EY08629. AE003779 refers to the contig number of the Drosophila genome project (Adams et al. 2000). The noncoding and coding regions of the acf1 transcript are depicted as open and filled boxes, respectively. The gray bar indicates the Acf1 polypeptide that was used to prepare anti-Acf1 polyclonal antibodies. (B) Western blot analysis reveals that acf1¹ is a null allele. Nuclear extracts derived from 0- to 12-h embryos of homozygous acf1¹ flies or wild-type (Canton S) flies were subjected to Western blot analysis with anti-Acf1 antibodies. (C) Western analysis of Acf1 expression in embryos of acf1 alleles. Crude lysates of 0- to 12-h embryos (Ito et al. 1999) of homozygous wild-type, acf1¹, acf1², acf1³, and acf1⁴ flies were subjected to Western blot analysis with anti-Acf1 antibodies. Acf1 is not expressed in acf1¹ or acf1² embryos, but its expression is not significantly affected in acf1³ or acf1⁴ embryos. Asterisks indicate nonspecific bands.