Human gene MOB: structure specification and aspects of transcriptional activity.
Prior investigation of human brain cDNA libraries revealed an evolutionarily conserved gene MOB that has been cloned in silico on chromosome 10. To elucidate its biological role, we performed structural and functional analysis of its transcripts. Applying an expressed sequence tag (EST) approach, we specified the sequence of the predicted MOB transcript and found another four exons to belong to the 5'- end of the MOB gene; the newly constructed MOB transcript was detected in vitro. Here, we report MOB to comprise at least 11 exons and 10 introns and to span more than 320 kb of the genomic sequence. We propose complex regulation of MOB gene activity at a transcriptional level, based on its expression pattern. Thus, in the human cerebellum, we discovered multiple alternatively spliced products of MOB differing in their coding portion; one of the alternative transcripts was demonstrated to lack the longest coding exon VII. MOB was expressed at very low levels in a wide spectrum of human tissues: most abundantly in the brain and in the kidney. Two transcription initiation sites were found for MOB and two alternative promoters were suggested to govern its expression. We believe that MOB activity is also regulated at the posttranscriptional level. In the constructed MOB transcript, the extended multiexon 5'-untranslated region (UTR) together with the weak context of the translation start ATG codon are considered as potent translator inhibitors. Modulation of MOB translation efficiency is proposed based on the appropriate alternative splicing events within the 5'-UTR. The MOB 3'-UTR is anticipated to mediate message instability. We thus suggest that this MOB transcript may be a labile short-lived molecule with strong regulation of its translational efficiency. We believe that MOB gene activity is controlled at least at the transcriptional and the posttranscriptional levels, strictly regulating the amount of the encoded protein product.
Vladychenskaya
Irina P
IP
Department of Human Molecular Genetics, Institute of Molecular Genetics RAS, Kurchatov sq., 2, 123182 Moscow, Russia. irinavl@img.ras.ru
Dergunova
Lyudmila V
LV
Dmitrieva
Veronica G
VG
Limborska
Svetlana A
SA
D024506:5' Flanking Region / Q000235:genetics; D017398:Alternative Splicing; D001483:Base Sequence; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D005091:Exons; D020224:Expressed Sequence Tags; D020869:Gene Expression Profiling; D005796:Genes / Q000235:genetics; D006801:Humans; D007438:Introns; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000235:genetics* / Q000378:metabolism; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D024363:Transcription Initiation Site; D014158:Transcription, Genetic / Q000235:genetics; D017855:Transferases (Other Substituted Phosphate Groups)
D018076:DNA, Complementary; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D020033:Protein Isoforms; C455440:SGMS1 protein, human; D017855:Transferases (Other Substituted Phosphate Groups)