We describe the isolation and characterization of @entity2829 cDNAs that are transcribed from a small gene family and encode a novel group of receptor-like kinases (RLKs). The distinctive extracellular domain of these novel RLKs includes a unique number and arrangement of @entity368 -rich repeats (LRRs), a @entity1521 -rich region (PRR), a putative protein degradation target sequence (PEST), and a @entity563 -rich region (SRR). The intracellular domain contains a putative @entity563 / @entity1889 protein kinase. To distinguish them from other reported RLKs, these novel RLKs were termed @entity368 -rich repeat transmembrane protein kinases (LTKs). Based on analysis of available deduced protein sequences, @entity69664 and @entity69665 were predicted to be 92.1% identical, while @entity69665 and LTK3 were predicted to be 97.5% identical. Though the three LTK proteins showed high homology, the region that most distinguished @entity69664 from @entity69665 and LTK3 was found in the extracellular domain, in the SRR. To differentiate between expression of the individual ltk genes, we used the reverse transcriptase polymerase chain reaction (RT-PCR) in combination with restriction enzyme analysis. While @entity69664 transcripts were constantly present in all tissues tested, @entity69665 and ltk3 transcripts were only detected in the endosperm. Furthermore, transcript levels for both @entity69664 and @entity69665 showed modulation during endosperm development, peaking at 20 days after pollination. These results suggest that members of the ltk gene family mediate signals associated with seed development and maturation.

The ltk gene family encodes novel receptor-like kinases with temporal expression in developing XXXX endosperm.

@entity69664 :: ('541658(Tax:4577)', 'Gene') :: ['ltk1', 'LTK1'] @entity69665 :: ('541659(Tax:4577)', 'Gene') :: ['LTK2', 'ltk2'] @entity2829 :: ('4577', 'Species') :: ['maize'] @entity368 :: ('CHEBI:25017', 'Chemical') :: ['leucine'] @entity563 :: ('CHEBI:17822', 'Chemical') :: ['serine'] @entity1521 :: ('CHEBI:26271', 'Chemical') :: ['proline'] @entity1889 :: ('CHEBI:26986', 'Chemical') :: ['threonine']
@entity2829 :: (4577,Species) :: ['maize']
