Human transcription factor Sp3: genomic structure, identification of a processed pseudogene, and transcript analysis.
The human transcription factor Sp3 has been widely studied at the translational level and has been described as a regulatory factor for a number of genes. Sp3 is currently characterized as a bifunctional transcription factor having the ability to behave as both an activator and/or a repressor in various promoter regions. Previous translational studies have attempted to determine the basis for these diverse functions with mostly contradictory evidence to date. Little data are available, however, concerning genomic structure, full-length cDNA, potential transcript variants, or location of translation initiation sites for the large isoform of the Sp3 gene. In this study, bacterial artificial chromosome (BAC) sequencing, reverse transcription-polymerase chain reaction (RT-PCR), genomic PCR, and database mining indicate that the Sp3 gene encompasses seven exons spanning more than 55 kb of genomic DNA on Chromosome 2. The 5' end of this sequence contains a large CpG island. This work also detected a processed pseudogene, psiSp3, located on Chromosome 13, spanning approximately 4.0 kb. Northern blot analysis detected three predominant transcripts at 4.0, 6.0 and 2.5 kb. Sequence analysis indicated that alternative splicing of exon 3 allows for multiple transcripts of Sp3. Each sequenced transcript possesses three to five potential translation initiation sites. This diversity at the level of gene expression will likely be key to understanding the diverse functions of Sp3.
Moran
Kelly M
KM
Department of Microbiology and Immunology, Georgetown University Medical Center, 3900 Reservoir Road, NW, Washington, DC 20057, USA.
Crusio
Robbert H J
RH
Chan
Connie H
CH
Grekova
Maria C
MC
Richert
John R
JR
D017398:Alternative Splicing; D001483:Base Sequence; D015152:Blotting, Northern; D045744:Cell Line, Tumor; D002882:Chromosomes, Human, Pair 13 / Q000235:genetics; D002889:Chromosomes, Human, Pair 2 / Q000235:genetics; D003001:Cloning, Molecular; D004247:DNA / Q000737:chemistry / Q000235:genetics; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics*; D005091:Exons; D020869:Gene Expression Profiling; D005796:Genes / Q000235:genetics; D006367:HeLa Cells; D006801:Humans; D007438:Introns; D019169:Jurkat Cells; D008297:Male; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics; D020033:Protein Isoforms / Q000235:genetics; D011544:Pseudogenes / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D051705:Sp3 Transcription Factor; D014157:Transcription Factors / Q000235:genetics*; D014158:Transcription, Genetic / Q000235:genetics
D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D020033:Protein Isoforms; D012333:RNA, Messenger; C497121:SP3 protein, human; D014157:Transcription Factors; D051705:Sp3 Transcription Factor; D004247:DNA