Table 4.

Comparison of bHLH Gene Occurrence in Arabidopsis and Other Eukaryotic Organisms Whose Genomes Have Been Sequenced

OrganismApproximate
 Number of GenesApproximate Number
 of Transcription
 FactorsNumber of
 bHLH ProteinsPercentage of
 Transcription Factors
 That Are bHLH Proteins
Saccharomyces cerevisiae*6,000771 (12.9%)50.6
Drosophila**14,000635 (4.5%)568.8
C. elegans**19,000669 (3.5%)355.2
Arabidopsis**26,0001533 (5.9%)1479.5
Human***35,0001850 (5.4%)174a9.4
  • * Mewes et al. (2002) and MIPS Comprehensive Yeast Genome Database;

  • ** Riechmann et al. (2000) and Ledent and Vervoort (2001);

  • *** Venter et al. (2001).

  • a Number taken from a database search of the human genome database.

  • The asterisks indicate the source of the data for number of genes, number of transcription factors, and number of bHLH proteins (except for Arabidopsis, which was reported in this study):