Rat thymosin beta 4 gene. Intron-containing gene and multiple retroposons.
Thymosin beta 4 (T beta 4), a 43-residue peptide of uncertain function, is widely distributed in most tissues of vertebrates. Southern blot analysis demonstrated that the rat genome contains many closely related T beta 4 sequences. Two distinct T beta 4 sequences were isolated by screening a rat genomic DNA library. Analysis of these clones revealed that they represent T beta 4 retroposons; they lack introns and contain stretches of poly(A) sequence at their 3' ends and direct repeats flanking the cDNA-like sequences. In order to isolate a T beta 4 intron-containing gene, DNA fragments that include T beta 4 introns were generated by polymerase chain reaction, using rat genomic DNA as template. Subsequent Southern blot analysis of rat genomic DNA with intron-specific probes demonstrated the presence of a single T beta 4 intron-containing gene. Upon screening the rat genomic DNA library with an intron-specific probe, two overlapping clones of the T beta 4 intron-containing gene were isolated. Further characterization and sequence analysis showed that the rat T beta 4 intron-containing gene has a 2-kilobase pair-long transcription unit containing two introns. The transcription initiation site and putative regulatory elements of the promoter were identified.
Varghese
S
S
Endocrine Unit, Massachusetts General Hospital, Boston.
Kronenberg
H M
HM
D000818:Animals; D001483:Base Sequence; D015139:Blotting, Southern; D004247:DNA / Q000235:genetics / Q000302:isolation & purification; D004251:DNA Transposable Elements; D007438:Introns; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D013947:Thymosin / Q000031:analogs & derivatives* / Q000235:genetics; D014158:Transcription, Genetic; D000099201:Thymosin beta(4)
D004247:DNA; D004251:DNA Transposable Elements; D012333:RNA, Messenger; D013947:Thymosin; D000099201:Thymosin beta(4)