AbstractThe localization of proteins can give important clues about their function and help sort data from large‐scale proteomic screens. Forty‐five proteins were tagged with the GFP variant YFP. These proteins were chosen because they are encoded by genes that display strong cell cycle‐dependent expression that peaks in G1. Most of these proteins localize to either the nucleus or to sites of cell growth. We are able to assign new cellular component GO terms to ASF2, TOS4, RTT109, YBR070C, YKR090W, YOL007C, YOL019W and YPR174C. We also have localization data for 21 other proteins. Noteworthy localizations were found for Rfa1p, a member of the DNA replication A complex, and Pri2p and Pol12p, subunits of the α‐DNA polymerase : primase complex. In addition to its nuclear localization, Rfa1p assembled into cytoplasmic foci adjacent to the nucleus in cells during the G1–S phase transition of the cell cycle. Pri2 and Pol12 took on a beaded appearance at the G1–S transition and later in the cell cycle were enriched in the nuclear envelope. A new spindle pole body/nuclear envelope component encoded by YPR174 was identified. The cell cycle‐dependent abundance of Tos4p mirrored Yox1p and these two proteins were the only proteins that were found exclusively at the G1–S phase of the cell cycle. A complete list of localizations, along with images, can be found at our website (http://www.yeastrc.org/cln2/). Copyright © 2004 John Wiley & Sons, Ltd.