Articles

Plants use photoperiodism to activate flowering in response to a particular daylength. In rice, flowering is accelerated in short-day conditions, and even a brief exposure to light during the dark period (night-break) is sufficient to delay flowering. Although many of the genes involved in controlling flowering in rice have been uncovered, how the long- and short-day flowering pathways are integrated, and the mechanism of photoperiod perception is not understood.

Chromatin structure, DNA methylation, and histone modifications act in a concerted manner to influence gene expression and therefore plant phenotypes. Environmental stresses are often associated with extensive chromatin rearrangements and modifications of epigenetic levels and patterns. Stress-tolerant plants can be a good tool to unveil potential connections between specific epigenetic modifications and stress tolerance capacity.

Understanding how the packaging of chromatin in the nucleus is regulated and organized to guide complex cellular and developmental programmes, as well as responses to environmental cues is a major question in biology. Technological advances have allowed remarkable progress within this field over the last years. However, we still know very little about how the 3D genome organization within the cell nucleus contributes to the regulation of gene expression.

Os pequenos RNAs conferem especificidade a um conjunto de processos celulares, coletivamente designados por silenciamento mediado por RNA, os quais controlam a expressão de muitos genes e mantêm num estado quiescente vírus e transposões. Devido ao seu tamanho, os pequenos RNAs não foram reconhecidos como moléculas reguladoras até muito recentemente.

A regulação epigenética é o processo pelo qual a atividade de um gene é modulada através de modificações covalentes do DNA, de histonas associadas ao DNA, ou da organização estrutural da cromatina em que está inserido. A utilização do termo regulação epigenética exige explicitamente que o estado do gene seja passível de ser herdado, ou seja, que possa ser estavelmente transmitido através de um ou mais ciclos mitóticos.