CIN‐TCP transcription factors: Transiting cell proliferation in plants

Abstract

Leaves are the most conspicuous planar organs in plants, designed for efficient capture of sunlight and its conversion to energy that is channeled into sustaining the entire biosphere. How a few founder cells derived from the shoot apical meristem give rise to diverse leaf forms has interested naturalists and developmental biologists alike. At the heart of leaf morphogenesis lie two simple cellular processes, division and expansion, that are spatially and temporally segregated in a developing leaf. In leaves of dicot model species, cell division occurs predominantly at the base, concomitant with the expansion and differentiation of cells at the tip of the lamina that drives increase in leaf surface area. The timing of the transition from one cell fate (division) to the other (expansion) within a growing leaf lamina is a critical determinant of final leaf shape, size, complexity and flatness. The TCP proteins, unique to plant kingdom, are sequence-specific DNA-binding transcription factors that control several developmental and physiological traits. A sub-group of class II TCPs, called CINCINNATA-like TCPs (CIN-TCPs henceforth), are key regulators of the timing of the transition from division to expansion in dicot leaves. The current review highlights recent advances in our understanding of how the pattern of CIN-TCP activity is translated to the dynamic spatio-temporal control of cell-fate transition through the transactivation of cell-cycle regulators, growth-repressing microRNAs, and interactions with the chromatin remodeling machinery to modulate phytohormone responses. Unravelling how environmental inputs influence CIN-TCP-mediated growth control is a challenge for future studies. © 2018 IUBMB Life, 70(8):718-731, 2018.

Identification, Characterization, and Expression Patterns of TCP Genes and microRNA319 in Cotton

“…Class II is further subdivided into the CINCINNATA (CIN) and CYC/TB1 subgroups. In addition to the TCP domain, several class II members possess an 18–20-residue arginine-rich motif [ 8 ]. This so-called R domain was predicted to form a hydrophilic α-helix or a coiled-coil structure that mediates protein–protein interactions [ 2 ].…”

WUSCHEL-related homeobox1 (WOX1) regulates vein patterning and leaf size in Cucumis sativus

“…In species with simple leaves, mutations of CIN-TCPs result in changes in leaf size, shape and curvature, consistent with their roles as growth repressors 40 . Five miR319-targeted CIN-TCPs in Arabidopsis , TCP2, 3, 4, 10, and 24, and their orthologs in snapdragon and tomato, were found to control leaf morphogenesis by limiting the number of pavement cells 22 , 25 , 41 , 42 .…”

Molecular cartography of leaf development — role of transcription factors

“…Transcriptome profiling of young wild-type snapdragon and cin mutant leaves allowed the identification of AmHISTI-DINE KINASE4 (encoding a homolog of Arabidopsis cytokinin receptor) and AmIAA3/SHY2 (encoding a homolog of the Arabidopsis AUX/IAA repressors of auxin signalling), as the direct downstream targets of CIN [68 ]. Interestingly, these two genes are expressed more strongly at the margins than at the medial region, similar to CIN, raising the possibility that CIN regulates growth suppression at the margins by modulating the balance between auxin and cytokinin signals [70]. On the other hand, direct identification of the margin and centreenriched genes in Arabidopsis enabled an analysis of their differential regulation in the tcp2/3/4/10 quadruple mutant [69 ].…”