Molecular characterization of two Brassica napus pollen-expressed genes encoding putative arabinogalactan proteins.
Two highly homologous cDNA clones, Sta 39-3 and Sta 39-4, corresponding to mRNAs highly expressed in Brassica napus cv Westar stamens were isolated by differential screening and characterized. Northern blot and in situ analyses demonstrated that Sta 39-3 and Sta 39-4 transcripts accumulate in pollen following the first pollen mitosis and are abundant at pollen maturity, thus identifying them as "late" pollen genes. Sta 39-3 and Sta 39-4 belong to a small gene family. Their predicted proteins share similarities with those deduced from recently isolated cDNAs encoding arabinogalactan proteins, which include a similar molecular mass (approximately 13 kD); high levels of alanine, proline, serine, and threonine, which are interspersed throughout the protein with no obvious repetitive motif; low levels of cysteine, histidine, tryptophan, and tyrosine; and hydrophobic N- and C-terminal ends. The Sta 39-3 and Sta 39-4 proteins may play a role in pollen germination and tube growth.
Gerster
J
J
Plant Research Centre, Central Experimental Farm, Ottawa, Ontario, Canada.
Allard
S
S
Robert
L S
LS
D000595:Amino Acid Sequence; D001483:Base Sequence; D001937:Brassica / Q000235:genetics*; D018797:Cell Cycle Proteins; D018076:DNA, Complementary; D005685:Galactans / Q000235:genetics*; D006023:Glycoproteins; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics*; D011058:Pollen / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D012689:Sequence Homology, Nucleic Acid
D018797:Cell Cycle Proteins; D018076:DNA, Complementary; D005685:Galactans; D006023:Glycoproteins; D010940:Plant Proteins; D012333:RNA, Messenger; C104295:Sta 39-3 protein, Brassica napus; C104296:Sta 39-4 protein, Brassica napus; C005653:arabinogalactan