High impact information on SAMDC

• The presence of introns is necessary for the SAMDC up-regulation process when the internal spermidine level is low [1].
• This sequence may help to keep the transcript of its downstream cistron at a relatively low level and function together with its own promoter in response to external stimuli or internal changes of spermidine and spermine to initiate and regulate SAMDC expression [1].
• When compared with other organisms, the plant SAMDC genes possess some distinct features because they are devoid of introns in the main open reading frame (ORF) but have an intron(s) in their 5' untranslated leader sequences, in which two overlapping tiny and small upstream ORFs (uORFs) are present [1].
• The pivotal roles of the plant S-adenosylmethionine decarboxylase 5' untranslated leader sequence in regulation of gene expression at the transcriptional and posttranscriptional levels [1].
• The double mutant of bud2 and samdc1, a knockdown mutant of another SAMDC member, is embryo lethal, demonstrating that SAMDCs are essential for plant embryogenesis [2].

Biological context of SAMDC

• Site-specific mutagenesis was performed on the AdoMetDC to introduce mutations at conserved cysteine (Cys(50), Cys(83), and Cys(230)) and lysine(81) residues, chosen by examination of the conserved sequence and proved to be involved in enzymatic activity by chemical modification [3].
• BUD2, encoding an S-adenosylmethionine decarboxylase, is required for Arabidopsis growth and development [2].

References