Core Cell Cycle–Related Gene Identification and Expression Analysis in Maize

Cell cycle is precisely controlled by numerous regulators. Although extensive studies have identified the cell cycle regulators in rice and Arabidopsis and classified into different gene families, relatively few cell cycle regulators were identified in maize. In this study, 110 putative core cell cycle–related genes in the maize genome were identified through sequence alignment analysis. Among them, 54 members of cyclin family were divided into the A-, B-, C-, D-, F-, L-, T-, and SDS-type subfamilies; 16 members of CDK family were partitioned into the A-, B-, C-, E-, F-, and G-type subfamilies; 19 members of E2F-DP family were separated into the E2F, PAP, DPB, CK, and DEL subfamilies; the remaining genes were nine ICK/KRPs, three EL2/SIMs, three CKSs, five Rbs, and one Wee1 kinase. Maize cell cycle–related genes unequally distributed on all chromosomes, and thirty-six pairs of them were identified as paralogs. The prediction of protein interaction found that 91 proteins were able to interact with each other forming 939 pairs of interactions with a probability more than 0.7. The expression analyses revealed that most of the cell cycle–related genes were expressed in all tissues. The transcription level of some genes in young tissues was higher than that in mature tissues of maize. Meanwhile, some genes from different families shared the similar expression pattern. Overall, the sequence characteristics and expression patterns of maize cell cycle–related genes vary with different gene families. Our results provide basic information for elucidating the functions of these genes in maize.