Here, at a glance, are developments Friday concerning the U.S. decision to hold direct talks with Palestine Liberation Organization representatives:

PLO-U.S. TALKSU.S. Ambassador Robert H. Pelletreau Jr. opened talks with the PLO and both sides said they hoped the dialogue would lead to a comprehensive Middle East peace.

"`Our discussions were very practical and characterized, I would say, by seriousness of purpose," Pelletreau said after the 90-minute meeting with a four-man PLO delegation. The ambassador implied there would be other meetings but did not say when.

REAGAN-PLO

President Reagan said America's "strong and steadfast" support of Israel's statehood persuaded the PLO to moderate its views.

Reagan called the opening in negotiations with the PLO "a great step forward," said peace will be achieved only "when the principals come together to negotiate." He said he made the decision to talk with the PLO because they accepted Israel's sovereignty and renounced terrorism "without fuzzing it up with ambiguous dialogue."

ISRAEL-PLO

The U.S. dialogue with the PLO is forcing Israel to reassess its policy, and politicians both left and right now are searching for a alternative plan for peace negotiations.

Foreign Minister Shimon Peres, leader of the center-left Labor Party, proposed elections in which Palestinians of the occupied lands would choose local leaders to negotiate with Israel.

Prime Minister Yitzhak Shamir, who leads the conservative Likud bloc, is considering "new moves" and aides say he recognizes the need for a credible Israeli plan.

Nimrod Novick, political adviser to Peres, said Israel must develop a peace plan capable of reducing international pressure.

"If we put an initiative on the table, we force all other parties to deal with it," he said. "If we sit quietly, we will be forced to deal with . . . someone else."

ISRAEL-UNREST

Soldiers killed four Palestinians in the occupied territories Friday after a funeral procession in Nablus escalated into street battles. Soldiers imposed a curfew, barring journalists and photographers.

Doctors said 20 people were wounded in Nablus, four of them critically. An army spokesman confirmed four killed and nine wounded.

An aide to Shamir said the day's outburst was evidence the United States should not have contacts with the PLO.

"This is the result of giving in to people of violence," Avi Pazner said.

ISRAEL-CHRISTMAS

Christmas tourism has dropped sharply because of the Palestinian uprising, and some hotel managers in Nazareth and Jerusalem, where many of the traditional festivities have been canceled, say they have no bookings at all for the holidays.

The ministry predicts that 70,000 visitors will arrive in December, a decline of 14 percent from 1987. Before the uprising began a year ago, it was predicting that 1988 would be a record tourism year because it coincided with the 40th anniversary of Israel's founding.