Cauliflower mosaic virus 35S (CaMV35S) promoter, short variant (~350 bp)
Truncated cauliflower mosaic virus 35S promoter spanning roughly the -343 to +8 region relative to the transcription start site, containing the full enhancer and core elements but omitting additional far-upstream sequence present in longer CaMV35S constructs. Retains essentially the full-length promoter's constitutive transcriptional strength in dicot plant tissues.
Origin: Cauliflower mosaic virus
Characteristics
Spans approximately -343 to +8 relative to the transcription start site, covering both subdomains mapped by deletion analysis (-343 to -90 and -90 to +8); sequences upstream of -343 were found to add no further increase in reporter activity, so this fragment retains essentially the same transcriptional strength as longer CaMV35S constructs while omitting non-essential upstream sequence (Odell et al. 1985). The retained region includes both tissue-preferential subdomains, giving expression detectable across leaf, stem, cotyledon, root, and radicle tissue (Benfey et al. 1989).
Applications: Used as a compact, full-strength alternative to longer CaMV35S promoter fragments in size-constrained plant expression or reporter constructs, and as the standard promoter fragment in many binary vectors for Agrobacterium-mediated dicot transformation.
Limitations: Omits sequence upstream of -343 present in some longer CaMV35S constructs, so it cannot substitute for constructs specifically testing far-upstream regulatory elements. Like other CaMV35S variants, it is markedly weaker in monocot species and largely inactive in pollen.