Component of the sequence-specific heterotrimeric transcription factor (nfya-1-NF-Y) which specifically recognizes a 5'-CCAAT-3' box motif found in the promoters of its target genes to regulate their expression and control cellular identity in particular tissue types. In association with the components in the nfya-1-NF-Y complex, represses the expression of the T-box transcription factor tbx-2 throughout larval development, which most likely restricts its expression to certain tissues. May act to repress txb-2 expression in conjunction with tbx-2 itself, which has an autoregulatory role (Probable). With the components in this complex, negatively regulates the expression of the homeobox protein egl-5 to spatially restrict its expression in tissues such as the head. May regulate egl-5 expression in association with the mes-2-mes-3-mes-6 complex