Chargaff difference analysis of the bithorax complex of Drosophila melanogaster

被引:13
作者
Dang, KD [1 ]
Dutt, PB [1 ]
Forsdyke, DR [1 ]
机构
[1] Queens Univ, Dept Biochem, Kingston, ON K7L 3N6, Canada
来源
BIOCHEMISTRY AND CELL BIOLOGY-BIOCHIMIE ET BIOLOGIE CELLULAIRE | 1998年 / 76卷 / 01期
关键词
base ratios; base clusters; Chargaff's second parity rule; open reading frames; transcription direction; stem-loops;
D O I
10.1139/bcb-76-1-129
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Much of the fruit fly genome is compact ("Escherichin coli mode"), indicating a genome-wide selection pressure against DNA with little adaptive function. However, in the bithorax complex (BX-C) homeodomain genes are widely dispersed with large introns ("mammalian mode"). Chargaff difference analysis of compact bacterial and viral genomes has shown that most mRNAs have the potential to form stem-loop structures with purine-rich loops. Thus, for many taxa if transcription is to the right, the top (mRNA synonymous) DNA strand has purine-rich loop potential, and if transcription is to the left, the top (template) strand has pyrimidine-rich loop potential. The best indicator bases for transcription direction are A and T for AT-rich genomes, and C and G For CC-rich genomes. Consistent with this, Chargaff difference analysis of BX-C genes and several non-BX-C genes shows that, whatever the mode, mRNAs have the potential to form stem-loop structures with A-rich loops. We confirm that many potential open reading frames in the BX-C are unlikely to be functional. Conversely, we suggest that a few unassigned open reading frames may actually be functional. Since apparent organization in the mammalian mode cannot be explained in terms of unacknowledged open reading frames, yet the fruit fly genome is under pressure to be compact, it is likely that many BX-C functions do no: involve the encoding of proteins.
引用
收藏
页码:129 / 137
页数:9
相关论文
共 26 条